[1] We Are Legion We Are Bob (Bobiverse 1-3) - Just finished this trilogy and really enjoyed it! It's well paced, has a very likable protagonist and has a nice sprinkling of programming/CS humor.
[2] Guns, Germs and Steel - Can't believe I waited so long to check this off my list. Very thorough and well written argument about how geography and environment shaped the modern world.
[3] Waking Up: A Guide to Spirituality Without Religion - Scientific and philosophical reasoning for why the self is an illusion. Covers a lot of ground without getting too heavy: Buddhism, mediation, neuroscience, religion, and more.