Anecdote 1: I have a translation of a Russian book of high school physics problems, most of which I can't solve. Anecdote 2: Michael Spivak's "Calculus on Mani

Anecdote 1: I have a translation of a Russian book of high school physics problems, most of which I can't solve. Anecdote 2: Michael Spivak's "Calculus on Manifolds" is famous as the hardest math textbook an engineer will have to tackle. Well, there are major theorems in that book that are "easy" exercises in Vladimir Arnold's Mathematical Methods of Classical Mechanics.