Typography in ten minutes

This is a bold claim, but i stand be­hind it: if you learn and fol­low these five ty­pog­ra­phy rules, you will be a bet­ter ty­pog­ra­pher than 95% of pro­fes­sional writ­ers and 70% of pro­fes­sional de­sign­ers. (The rest of this book will raise you to the 99th per­centile in both categories.)
Matthew Butterick, Practical Typography

Un classique à ne pas oublier.