Teach Yourself Logic 2020:A Study Guide [pdf]

tl;dr Teach Yourself Logic 2020: A Study Guide by Peter Smith

This book discusses what I would describe as "formal logic" or philosophy. In my opinion that is for those interested in pure math or philosophy. This book is a study guide but not a text book. In other words you are not going to learn this kind of logic from the study guide.

My guess is many programmers and engineers would be better served first learning what I call "symbolic logic" or "digital logic". It is not hard to learn. I taught myself from a book. However, I think it would be more interesting and more fun to take a class, given the opportunity.