I tried some solutions, but they don't really work nicelhy (or don't work at all):

• add a link to an html file inside a page
• use iframe
• merge the sphinx conf.py from the book into the one of sphinx

Is there someone that every tried to accomplish this succesfully?

Ideally I would like to have the book as one of the main top-level pages and be able to still see the original theme header above in order to switch pages