You have the possibility to create an ebook in makdown, using then the pandoc software. 

You will get all information here: [Creating an ebook with pandoc](https://pandoc.org/epub.html) 

*pandoc* is available for Windows, linux, macOS, Chrome OS. 

Here is a few information extracted from this site.

A simple example: 

```
% My Book
% Sam Smith

This is my book!

# Chapter One

Chapter one is over.

# Chapter Two

Chapter two has just begun.
```

And you can generate the .epub with the command

	pandoc mybook.txt -o mybook.epub
	
You can simply insert images as usually in markdown:

	![Imag](images/ex.jpg)
	
Things become more tricky if you want to personalise the format of the book. You will need for example to write a specific .css file. 

However, if you want to build many books with basically the same format, a single .css file can be used for all.