1. Orsay Classics (Mathematics), Blue Book Series of Mathematical Orsay Courses (16 Small Edition), real questions over the years (necessary, because mathematics pays attention to thinking, there are almost no books to teach us how to think, at least I haven't met them yet. Be sure to think for yourself and ponder the thinking process. You will have many surprises in the repetition of proof and guess.

2. Physically, 1. Cheng jiafu series,