Proofs

This book gives a wonderful overview of proof theory. That is the art of crafting mathematical proofs from intuition and understanding. The author deliberately breaks from the traditional higher maths method of learning through proof examination; which makes the book feel much more like a lecture than self-learning. The introductory chapter makes proving theorems feel like a kind of magic. In particular using the pigeonhole principle on those first few problems. The difficulty level was tame for what I assumed was going to be a higher maths book. The readability was simply amazing, such that both my personal understanding of the topics (and tangent material) was driven by curiosity.