This Sigil release is a mix of bug fixes and new features for both epub2 and epub3 users. Fixed the bug on Windows where smart right single quotes used for apostrophes couldn’t be added properly added to a user word list. This one has been around for a while.
Tool Description as in https://sigil-ebook.com/
If you are looking for an extremely simple and an effective eBook creator software, EPUBee Maker could just be the solution for your computer. This program is an add-in for the Microsoft Word which you can see as the “ePUBee Maker” option on your MS Word toolbar post the installation.
Tool Description as in http://merabheja.com/best-free-ebook-creator-software-for-windows/
Scribus is an Open Source DTP (Desktop Publishing) application for Linux and other flavors of Unixand Unix-like systems, including Mac OS X , as well as OS/2 and eComStation respectively, and Windows 2000 or later. This Wiki has been created in order to give users a place to put HOWTOs, tips or ideas on using or enhancing Scribus. Large parts of the documentation available here have been contributed by Scribus users.
Tool Description as in https://wiki.scribus.net/canvas/Scribus
Calibre started life on 31 October, 2006, soon after the release of the SONY PRS-500, the first e-ink based reader to be sold commercially in the US. At the time, I was a graduate student, with a lot of time on my hands. The PRS-500 did not work at all with Linux, my operating system of choice, so I decided to reverse engineer the USB protocol that it used, to get it working on Linux. Calibre is a powerful and easy to use e-book manager. Users say it’s outstanding and a must-have. It’ll allow you to do nearly everything and it takes things a step beyond normal e-book software. It’s also completely free and open source and great for both casual users and computer experts.
Tool Description as in https://calibre-ebook.com/about#features
Image Credit: https://calibre-ebook.com/
Exe-eBook creator is a freewareebook compiler for TreePad files. It enables you to create an executable (program) from a TreePad .tpd or .hjt file. This single “exe-file”contains the TreePad database as well as the TreePad Viewer program.
Tool Description as in http://www.exe-ebookcreator.com/
Image Credit: http://www.exe-ebookcreator.com/