Here's a flavor of how this went:
Driscoll: So how did you end up becoming an author of Python books?
Lott: Most roles in my career more or less just happened to me, but becoming a writer was a conscious decision.
In this case, I had decided that there could be value in teaching the Python language and the associated software engineering skills. I started to collect notes for a book in 2002. By 2010, I had tried self-publishing several books on Python.
When Stack Overflow started, I was an early participant. There were many interesting Python questions. The questions showed gaps where more information was needed about Python specifically and software engineering in general. Over a few years, I answered thousands of questions about Python and somehow built up a large reputation.