The introduction to Programming in Emacs Lisp was my first contact with Lisp. And the reason I took it up - the excuse I used to cover up my insatiable curiosity - was that I was writing my diary using emacs, and since emacs was all about customization, it should be possible to create a keyboard shortcut to insert the current date and time of day.

And down the rabbit hole I went. So, in a way, Bob Chassell contributed to me becoming a programmer.