He taught in the classes préparatoires (preparatory classes for the grandes écoles) of prestigious high schools such as Henri-IV and Louis-le-Grand, before ending his career as an inspector general (1994 to 2001). He was deeply involved in education: he directed the RMS (Revue de mathématiques spéciales) from 1974 to 2007, published textbooks, and, as early as 1968, worked on the evolution of mathematics teaching — work that culminated in the 1969 publication of Mathématiques modernes (Modern Mathematics) by Éditions du Seuil. But it was probably as a popularizer that André Warusfel left his strongest mark. It began with a first book, published at the age of 23, Les Nombres et leurs mystères (Numbers and Their Mysteries), reissued in 1980. A fan of Ernő Rubik's Cube, he published a best-seller with Éditions Denoël in 1981, Réussir le Rubik's Cube (Solving the Rubik's Cube), which sold nearly 400,000 copies! Another book, some twenty years later (with journalist Albert Ducrocq), would meet with some success: les Mathématiques, plaisir et nécessité (Mathematics, Pleasure and Necessity) (Vuibert).