Foreword

The author would like to thank:

Mario Carneiro

Leonardo de Moura

Sebastian Ullrich

Gabriel Ebner

Jonathan Protzenko

The Lean Zulip community.

Each and every contributor to Lean4, Mathlib, and the broader Lean ecosystem.

This book is dedicated to the memory of Philip Elliot Bailey (31 January, 1987 - 9 December, 2023).