Searching for the answer to my original question
Can Ghost be used to write blogs and technical books at the same time I discovered Discourse and fell in love with it.
After reading the article How to use Ghost and Discourse together, I got even happier envisioning the seamless weaving of data between these two platforms.
I am still missing one piece of functionality - being able to write blogs (hello, Ghost) and technical documents that look like created with Gitbook
I used Gitbook in my past life frequently but this solution does not naturally fit into my integrated Ghost+Discourse platform.
One possibility might be DocuHub - A Modern Documentation Theme for Ghost, associated with some fancy footwork:
With the Routes & Collections you can separate your content. For example, having all blog posts on the index(/) page and having all doc posts under the /doc route.
as this may not fit naturally in my Ghost+Discourse platform.
I will appreciate any comments