BOOK File

What are BOOK files and how to open them

Are you having problems opening a BOOK file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your BOOK files.

What is a BOOK file?

BOOK files have multiple uses, and Cybiko Cybook eBook is one of them. Read more about the other uses further down the page.

Cybiko Cybook eBook

These BOOK files contain the audio ebooks used on the Cybiko, a Russian handheld computer released in April 2000. Cybiko was used to play games, text with friends, and listen to music. The MP3 player add-on combined with a SmartMedia card was used to listen to the audio ebooks.

How to open BOOK files

Important: Different programs may use files with the BOOK file extension for different purposes, so unless you are sure which format your BOOK file is, you may need to try a few different programs.

While we have not verified the apps ourselves yet, our users have suggested eight different BOOK openers which you will find listed below.

Last updated: August 24, 2026

All known file formats using extension .BOOK

While Cybiko Cybook eBook is a popular type of BOOK-file, we know of 4 different uses of the .BOOK file extension. Different software may use files with the same extension for different types of data.

FrameMaker book

These BOOK files contain the content created in Adobe FrameMaker, an authoring and publishing software. FrameMaker is a powerful content creation tool that makes working on content effortless. You can reuse and maintain consistency if you move your content to FrameMaker.

ICE Book Reader eBook

These BOOK files contain the imported TXT, RTF, HTML, and MS Word documents used in ICE Book Reader, a software used to make reading larger text files more convenient and effective. This software helps reduce the deterioration of eyesight. It provides a more comfortable reading experience.

MaxiDesk Phone Book

MaxiDesk Phone Book files store contact and directory listings created by the Amiga application MaxiDesk, which is a desktop utility suite published by MaxiSoft. The phone book component allows users to save names, addresses, phone numbers and related contact details for later retrieval, printing or management within the MaxiDesk environment.

These files are produced by MaxiDesk itself when a user saves their address book or phone directory. Later, the same application opens, edits or exports the saved entries. MaxiDesk Phone Book files are not designed for compatibility with non-MaxiDesk programs, since the file layout matches the internal data structures used by MaxiDesk for organizing fields such as name, address, phone number and possible categories that the program supports.

The file begins with a characteristic header: the ASCII string PHONEBOOKFILE.1 followed by a newline, and another line feed, at the very start of the file. This signature appears at offset zero.

Various apps that use files with this extension

These apps are known to open certain types of BOOK files. Remember, different programs may use BOOK files for different purposes, so you may need to try out a few of them to be able to open your specific file.

Help us help others

File.org helps thousands of users every day, and we would love to hear from you if you have additional information about BOOK file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.