Here is a necessarily incomplete list of books that were formative in my thinking (or that I really just enjoyed).
Immortality: The Quest to Live Forever and How It Drives Civilization by Stephen Cave
Curiosity: How Science Became Interested in Everything by Philip Ball
Little Science, Big Science by Derek J. de Solla Price
Geek Sublime: The Beauty of Code, the Code of Beauty by Vikram Chandra
Gödel, Escher, Bach: An Eternal Golden Braid by Douglas R. Hofstadter
Ignorance: How It Drives Science by Stuart Firestein
Finding Meaning in an Imperfect World by Iddo Landau
Four Thousand Weeks: Time Management for Mortals by Oliver Burkeman
A Guide to the Good Life: The Ancient Art of Stoic Joy by William B. Irvine
Nonzero: The Logic of Human Destiny by Robert Wright
Chaos: Making a New Science by James Gleick
The Clock Of The Long Now: Time and Responsibility by Stewart Brand
Where Good Ideas Come From: The Natural History of Innovation by Steven Johnson
What Technology Wants by Kevin Kelly
Out of Control: The New Biology of Machines, Social Systems, & the Economic World by Kevin Kelly
Why Greatness Cannot Be Planned: The Myth of the Objective by Kenneth O. Stanley and Joel Lehman
Mathematical Games columns by Martin Gardner
In the Beginning...was the Command Line by Neal Stephenson
The Stuff of Thought: Language as a Window into Human Nature by Steven Pinker
Steve Jobs & the NeXT Big Thing by Randall E. Stross
Consider Phlebas by Iain M. Banks
Mr. Penumbra's 24-Hour Bookstore by Robin Sloan
The Yiddish Policeman's Union by Michael Chabon
The Sirens of Titan by Kurt Vonnegut
The Baroque Cycle by Neal Stephenson
36 Arguments for the Existence of God: A Work of Fiction by Rebecca Newberger Goldstein
The Three-Body Problem trilogy by Liu Cixin
To Rise Again at a Decent Hour by Joshua Ferris
The First Fifteen Lives of Harry August by Claire North
Aurora by Kim Stanley Robinson
Collected Fictions by Jorge Luis Borges