Comment by WillAdams

One early tool in this space was Navipress (which AOL bought out and made into AOLpress) which is notable for having been used by a certain Tim Berners-Lee to write a book:

https://www.w3.org/People/Berners-Lee/Weaving/

https://www.goodreads.com/book/show/821987.Weaving_the_Web