I wrote and self-published a book in 2013 that definitely fits some definitions of success[1]. Sales to date total a little over $30,000, plus some consulting gigs.
I'm also trying to get into the book writing business. Can you tell me what tool you use to write the book? I was using Gitbook.io but it was buggy and not formatting well.
I wrote all of my own tools. The book itself is written in Markdown, and I use the Redcarpet gem to turn it into HTML. From that, I convert it into PDF and the ebook formats using Docverter.