Calibre 9.7: A complete guide to organizing and editing your ebooks

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Managing a digital library with hundreds or thousands of titles can become utter chaos without the right tools. Calibre 9.7 is designed to bring order to this ebook mess , refining already powerful features and polishing key details to make reading and daily organization much easier.

We're talking about a completely free, open-source project , very popular among readers in Spain and throughout Europe, which serves not only as an ebook viewer but also as a true management center for massive collections. In this version, Calibre 9.7 focuses on three key areas: improving the reading experience, facilitating advanced organization of annotations and metadata, and strengthening the stability of the content server and device connectivity.

What is Calibre and why is it so useful for organizing ebooks?

Calibre is a long-established, cross-platform, and free application that allows you to manage ebook libraries on Windows, macOS, and GNU/Linux. Its philosophy is simple: you control your library, your formats, and your devices, without subscriptions or limited versions.

With Calibre you can add and catalog ebooks , convert between formats (EPUB, AZW3, MOBI, etc.), modify metadata, download covers, send books to physical readers, read directly from your computer, and even set up a small web server to access your collection from your browser.

One of its great strengths is that it handles huge collections without breaking a sweat : manuals, novels, technical documents, notes, newspapers converted to eBooks… Everything is uploaded to the same database and organized using tags, authors, series, ratings, custom columns, and virtual libraries.

Furthermore, the program follows a policy of very frequent updates . New versions with additional features or bug fixes are released regularly. Calibre 9.7 fits into this continuity approach: it doesn't revolutionize everything, but it introduces a series of practical improvements that are very noticeable when using the program daily.

Key new features in Calibre 9.7 focused on reading and annotation

Version 9.7 arrives with a package of changes focused on the book viewer, the annotation browser, and the web reading server . There are no major overhauls, but there is some serious fine-tuning that improves usability.

On one hand, the eBook viewer is better adapted to touch devices and touchpads. The pinch-to-zoom gesture now works consistently on both touchscreens and laptop touchpads, directly adjusting the font size.

On the other hand, the annotation browser represents a significant leap forward in organization: it allows you to group notes and highlights by virtually any field in the database , from author to series, including tags or custom fields. For students, researchers, or readers who take a lot of notes, this is pure gold.

In addition, the integrated content server gains robustness: it debuts a complete offline mode when using HTTPS , so you can continue reading even if the network fails, and it corrects annoying errors in searches from the browser.

Improvements to the eBook viewer: touch gestures and reliable saving

Calibre's integrated viewfinder has always been one of its strengths, but in this version attention has been paid to details that affect the actual comfort of reading , especially on modern laptops.

Starting with Calibre 9.7, the pinch gesture on the touchpad or touchscreen is used to adjust the font size in the book, instead of applying inconsistent zoom. This makes switching between devices more natural, because the gesture behaves the same everywhere.

This unified interface is a great benefit for those who read on ultrabooks, convertibles, or tablets and are used to manipulating content with their fingers. Adjusting readability on the fly without navigating through menus is especially appreciated with long texts or when eyes are tired.

Along with the gestures, a bug introduced in a previous version has been fixed that prevented annotations and reading progress from being saved correctly within ebook files. This could cause highlights to be lost when reopening the book, or require manually re-entering the page where the reader left off.

In Calibre 9.7 this behavior is reliable again: notes, comments and the last page read are saved in the file itself , so that when you resume reading, even on another computer, you continue exactly where you were and with all your marks intact.

Annotation browser: advanced organization of notes and highlights

Anyone who uses Calibre for studying, researching, or working with extensive documentation knows how frustrating it is to waste time searching for a specific highlight among dozens of titles. That's why one of the most interesting new features in Calibre 9.7 is the new, more flexible annotation browser.

Now, entries can be grouped by any field in the database : author, series, tags, date added, custom columns, etc. This allows for very powerful classifications without leaving the program itself.

For example, a student can group notes by subject or course using specific tags. A researcher can organize highlights by project or line of work, and a regular reader can filter annotations by genre, collection, or even the device on which they were read.

This grouping feature makes locating a specific note much easier. Instead of opening book by book and searching, you work from a global view of notes , where you can quickly browse through the highlights scattered throughout the library.

Combined with the correction of the bug that prevented saving annotations and the last page read, the result is that Calibre 9.7 becomes a much more robust tool for managing information within ebooks , both in academic and professional contexts.

Content server: offline mode with HTTPS and more stable search

Another key component of Calibre is its integrated content server , which allows access to the library from any browser (computer, tablet, mobile) as if it were a personal cloud. Version 9.7 includes two significant improvements to this component.

The first is the addition of a fully offline mode when connecting via HTTPS . This means that once the browser has loaded the necessary content, you can still access the books even if your internet or local network connection drops.

This behavior is especially useful for travel, unstable connections, or environments where the Wi-Fi signal is intermittent . If you've already opened the book through Calibre's server, you can continue using it as if it were on your local machine, while also maintaining encrypted communication.

The second improvement relates to searching within books opened from the server . Bugs that prevented the internal search function from working correctly have been fixed, as well as issues opening results from full-text searches in the browser.

With these adjustments, using the Calibre server as a central reading point on the web, mobile devices, or tablets becomes smoother. Navigating between titles and jumping from a global search to the relevant excerpt within the book are now more predictable and less prone to glitches.

Full-text search, overall stability, and cover management

Beyond the server, Calibre 9.7 dedicates part of its changes to polishing the full-text search tool , which allows indexing all the content of the library to locate words or expressions within any book.

This version corrects several minor bugs in the full-text search view, improving its stability and reliability . While not detailing each individual case, the goal is to ensure that indexes are generated correctly and that results point accurately to the correct book and excerpt.

This feature is especially useful for very large subject libraries : collections of scientific articles, databases of legal rulings, technical manuals, etc. Being able to find on the fly where a concept appears in the entire collection saves a great deal of time.

Another issue that has been fixed is a problem with cover assignment when adding new files to book records that didn't yet have a cover. In some cases, the cover wasn't associated correctly, leaving the entry visually incomplete.

With Calibre 9.7, cover management is once again consistent: the image is correctly applied to the record when new formats are added , helping to maintain a visually organized library. For many users, identifying a book by its cover is faster than reading the title and author, so this detail is significant.

Advanced metadata management: the foundation of a well-organized library

One of Calibre's greatest strengths is its ability to work with comprehensive and customizable metadata . Metadata is information that isn't always immediately visible (author, publisher, series, tags, comments, date, identifiers, etc.), but it allows for very precise organization of a collection.

Calibre allows you to configure metadata download and processing options in detail . In the Preferences section, you can choose the sources from which the information will be obtained (Google, Amazon, Open Library, and others), as well as the priority assigned to each source.

You can also define exactly which fields will be downloaded : author, publication date, synopsis, series affiliation, issue number within the series, rating, tags, etc. This way, each user can adapt the level of detail to their needs: from those who only want the title and author, to those who build a very detailed cataloging system.

Another important advantage is that Calibre allows you to control how this metadata is formatted : name and surname order, handling of existing comments (replacing or adding), date formatting, and more. This is key to maintaining consistency in libraries with thousands of records.

In addition, the application offers very powerful utilities for modifying metadata in bulk , downloading information and covers from the Internet for several books at once, or even creating custom fields to reflect specific data, such as "subject", "project", "reading status" or any classification you can think of.

Integrated ebook editor: HTML, CSS and advanced tools

Beyond library management, Calibre includes a complete ebook editor capable of working directly with formats such as EPUB, KEPUB (Kobo), and AZW3 (Kindle). This editor is designed for those who need to go a step further and edit the internal content of their books.

The editor displays the HTML code and CSS stylesheets that make up the ebook, along with a preview panel that updates almost in real time as changes are made. This allows you to immediately see the effect of the modifications.

When you open a book with the "Edit book" option, an internal file explorer appears that lists the different components of the ebook : HTML chapters, CSS stylesheets, images, metadata files (content.opf), table of contents (toc.ncx), embedded fonts, etc.

From there you can perform actions such as renaming files, merging multiple HTML or CSS files into one, changing extensions, deleting unused resources, importing new images or fonts, or creating blank files to add additional content.

In addition, the editor offers tools geared towards advanced work with code: search and replace with regular expressions , saving of frequent searches, a Python-based "function" mode for performing complex text transformations, and a function to search ignoring intermediate HTML markup (useful when the tag cuts off a phrase).

Version control: checkpoints and milestones in ebook editing

When making extensive changes to books, it's helpful to have a system for reverting if something goes wrong . Calibre addresses this with two complementary mechanisms: checkpoints and milestones.

Checkpoints allow you to save the current state of the workbook before making significant changes. If you're not satisfied with the result, you can revert to that exact point. They can be created manually from the Edit menu and are also generated automatically when you run certain global tools, such as bulk search and replace.

Milestones function as more global status markers. They are created using the corresponding menu option and allow you to revert the entire book to a specific point in its development , even if the changes affect many different files within the ebook.

From the milestones view, you can compare the current state of the book with a previous milestone using the ebook comparison tool, or click "Revert to" to undo all changes made since then.

Thanks to this combined system, the Calibre editor offers a very comfortable level of security and control : it is possible to experiment, clean code, restructure chapters or modify styles knowing that you can always return to a previous known version.

Live preview and splitting of long HTML files

The preview panel is another key feature of the editor. It shows how the text will look when rendered by a reader , updating live every time you stop typing for a second or two.

In addition, the preview is synchronized with the editor: when you move the cursor in the code, the preview follows its position , and when you click on a point in the book in the preview, the cursor automatically jumps to the corresponding place in the HTML.

This panel is also very useful for splitting very long HTML files . By activating "split mode" under the preview, you can place the mouse over the exact spot where you want to cut the file. A green line indicates the break point, and clicking it splits the file in two, automatically updating links and references.

It's even possible to automatically split an HTML file into multiple locations, for example, at each heading (h1, h2, etc.) or at each tag with a certain class . This is very useful for converting imported books with huge chapters into a more manageable structure for e-readers.

It's important to remember that, while the preview is very accurate, it doesn't replace the final test on a real reader . Some aspects, such as page margins, precise page breaks, or the behavior of certain embedded fonts, may vary between devices.

Edit HTML and CSS with smart help

Calibre's editor offers advanced syntax highlighting and contextual help to make working with HTML and CSS easier, even when dealing with complex documents.

Among its features are visual highlighting of paired tags , keyboard shortcuts to jump to the opening or closing tag, quick selection of a tag's content, and red underlining of invalid code.

Spelling is also highlighted in the visible text (taking into account the language specified in the lang attributes) and in the CSS code within <style> tags. Special characters such as hard spaces or hyphens are marked for easy detection.

Another particularly useful feature is the auto-completion of file paths and anchors . When you start typing the name of an image, HTML file, or stylesheet, the editor suggests possible matches and allows you to complete them with the Tab key, even using only a fragment of the name.

The completion feature also works with internal anchors: after typing the # character, all available anchor points in the destination file are displayed along with a short descriptive snippet, which greatly speeds up the creation of internal links in books with many chapters.

Finally, support for reusable snippets allows you to save frequently used pieces of HTML or CSS code (e.g., warning boxes, quote blocks, calls to action) and paste them with a few keys, including placeholders that you can quickly jump to.

Calibre's main interface: library, search, and visual organization

Calibre's graphical interface provides access to all library management, conversion, and device delivery functions . It is organized into a main toolbar, a book list, a tag browser, a details panel, and optionally, a cover box or shelf view.

From the "Add books" button, you can import individual files, entire folders, compressed files (ZIP, RAR, 7z), or create empty entries. Calibre reads internal metadata and can also extract information from the filename itself using configurable regular expressions.

The “Modify metadata” actions allow you to edit the record of one or more books , download information and covers from the Internet, copy and paste metadata between records, or merge duplicate entries by combining their formats.

Book conversion is offered both individually and in bulk, with specific options to adjust the output to the target device . For large collections, the "Create Catalog" function generates complete listings in formats such as EPUB, MOBI, or CSV, useful for inventories or external queries.

The search system is extremely powerful: in addition to the basic search in the top bar , there is an advanced search dialog box that allows you to build complex queries with specific fields, logical operators, regular expressions, filters by dates, file sizes, number of tags, etc.

Tag explorer, virtual libraries, and display modes

The tag explorer is a key tool for easily navigating large collections. It allows you to filter by authors, series, tags, publishers, ratings , custom columns, and user categories.

Clicking on an item restricts the book list to those matching that value. Clicking repeatedly toggles between "show only those that have it," "show those that don't have it," or "remove the filter." Multiple filters can be combined by holding down keys such as Ctrl or Shift.

In addition, Calibre allows you to create user categories and hierarchies within tags , which are very useful for organizing genres, projects, or any custom classification. Hierarchical elements are displayed with expandable triangles and support specific searches.

To view only a portion of the library without physically moving the books, virtual libraries can be used . These are persistent filters that display only the books that meet certain criteria (for example, "Read," "Unread," "Spanish Science Fiction," etc.), as if they were separate sections.

As for the view, in addition to the classic row list, Calibre offers a cover chart , a bookshelf view with spines grouped by author, date, rating, etc., and a single-row cover browser. Everything can be customized in the preferences, adjusting sizes, backgrounds, and text displayed under the covers.

Connecting to devices, server, and sharing content

Calibre isn't limited to computers: it's designed to work seamlessly with e-readers, tablets, and mobile phones . When a compatible device is connected, a dedicated icon appears, allowing you to view, send, and delete books from its main memory or memory cards.

You can define the folder structure and file name that will be used when sending books to each device using very flexible templates, which allows you, for example, to group by author, series, language or any other criteria.

The "Save to disk" function allows you to export books with all their formatting and metadata , maintaining a consistent organization that can then be re-imported without losing information. It is ideal for external backups or migrations between computers.

The "Connect and Share" menu provides access to the web content server , allows you to connect to folders as if they were devices, and configure email delivery of books. This enables you to set up anything from a simple local synchronization to a small, home-based "cloud ecosystem."

On Linux, Calibre 9.7 also includes a significant fix for advanced users: a bug in the MTP driver that could cause unexpected crashes when connecting devices with very large libraries has been resolved . Starting with this version, managing tablets and phones via MTP is much more stable.

Keyboard shortcuts, quick view, and notes associated with authors and series

For those who spend many hours in Calibre, keyboard shortcuts are essential. The program includes combinations for almost everything: adding books, converting, sending to a device, modifying metadata, switching panels, opening advanced search, browsing annotations, managing virtual libraries, and more.

One particularly convenient feature is Quick View , which opens a panel or secondary window displaying books related to the selected cell's value (author, tags, series, publisher, custom column, etc.). This makes it possible to see, for example, all of an author's books without switching from the main view.

Calibre also allows you to add notes to authors, series, tags, publishers, and other items . By right-clicking on the name in the tag browser or the details panel, you can create or edit a note, which will then be displayed with a small pencil icon.

These notes support basic formatting, links, and images, and are used to document relevant information about an author or collection : biographies, links of interest, reading reminders, recommended order of a saga, etc.

Over time, all these small functions add up: the library is not only more organized, but it also becomes a very comfortable work and consultation environment centered around electronic books.

Overall, Calibre 9.7 is an update that reinforces what the program already did well: reading is more comfortable thanks to touch gestures and reliable saving of annotations, organization is improved with a much more powerful note browser and very fine metadata tools, the content server gains in stability and offline mode, and integration with devices and systems like Linux becomes more robust, consolidating Calibre as the go-to option for managing large and complex ebook libraries.