I’m going to start a new book first thing in the morning when I wake up. 

What should it be? 

My criteria - fiction, engrossing, philosophical (by which I mean concerned about how to live well), well written. 

Recent reading:
3 body problem
Flowers for Algernon
Everything by Ursula le Guin

Have you considered reading "Siddhartha" by Hermann Hesse? It meets your criteria of being fiction, engrossing, philosophical, and well-written. It's a thought-provoking novel about the journey of self-discovery and finding true meaning in life.