Writing Without Teachers by Peter Elbow -- I think anyone can become a strong writer by following the iterative process in this book How Music Works by David Byrne -- innocuous title, amazing exploration of music by the contexts that shape it: spatial, performance, tech, etc

"Human Behavior and the Principle of Least Effort" by George Zipf Explains so much, from the evolution of language to why people use the "available" tool for the job instead of the "best." Also, why people will not change their existing beliefs until they have failed.

The Extended Phenotype by @RichardDawkins. Baffling title (to most folks), but utterly brilliant & mind-blowing book.

The Price of Tomorrow - and it’s something everyone should read.

The Red Book by Carl Jung found me at just the right time. His explanation of his own archetypes reinforced lessons I've learned through trauma, trial and error. Know they self, know the other.

Economic Facts & Fallacies by @ThomasSowell completely changed my life. I was in middle school and had read Hayek / Friedman / Hazlitt but no one wrote as clearly and powerfully as Sowell IMHO. That book made me want to begin learning for myself in my own time.

The Art of Living by Epictetus--translation by Sharon Lebell is an easy to read, pragmatic book to keep by your side to improve daily living through Stoicism.