I'm Al Sweigart, author of several free programming books. My latest book is on recursion and recursive algorithms. AMA!
Recursion is a topic that a lot of programmers find intimidating. In 2018 I started doing research into the topic and found it isn't recursion that is difficult so much as that it's poorly taught. I started putting together a list of what makes recursion challenging to learn and it eventually turned into an entire book. It has some neat examples with a fractal creator and "Droste effect" recursive image maker. Ask Me Anything about recursion, Python, or teaching people to code.
I recently did an interview on The Real Python podcast about the book: Episode 124: Exploring Recursion in Python With Al Sweigart
The book is free online, but you can also buy print books directly from the publisher, No Starch Press. (They give you the ebook for free with purchase of the print book.)
(Go ahead and make recursion jokes, like links in your comment that link back to comment, but keep them under the official recursion joke thread.)
EDIT: I'm logging off for the night but can resume answering questions in the morning.
EDIT: Back online and 44 new comments. "Let us go," as the gamers say.
EDIT: Heyas, I'm done for the day. Thanks to everyone who asked questions!