Quantum Mechanics , by L.D. Landau and E.M. Lifshitz

  • This is Vol. III of the Course of Theoretical Physics

  • This book is not required , and the course will not follow it (or any other text) closely. The foundations part (chapters I and II) is very hard to understand, but the rest is very good. It's an excellent reference that you'll be likely to use for as long as you stay in physics. However, if you like a different book better, choose that.