“This is a collection of the forty How Euler did it columns that appeared on MAA Online between November 2003 and February 2007”. Each column deals with a particular result by Euler, and the columns have been grouped thematically: geometry, number theory, combinatorics, and analysis. Among Euler’s best known results, the Euler-Lagrange condition from the calculus of variations or his investigation of the gamma function are missing from these columns, but the rest are here: his solution of the Basel problem, his polyhedral formula, the divergence of the sum \(\sum 1/p\) of the inverse primes, his version of the quadratic reciprocity law, and many more are discussed at length, and in a manner that makes the book accessible to undergraduates.
The book is very well written and a joy to read.