+1 to Strogatz's Chaos book - this was the first textbook I ever read cover to cover, almost like a novel, because of how exciting it was. I also really liked

+1 to Strogatz's Chaos book - this was the first textbook I ever read cover to cover, almost like a novel, because of how exciting it was. I also really liked self studying Strang's Linear Algebra. Another one that comes to mind is Naive Set Theory by Halmos - it's a very short and well written introduction to set theory for practitioners but it still manages to get you thinking very deeply.