IN October, 1941, I was invited to give a course of lectures at the New School for Social Research in New York City on the general topic, "Mathematical Recreations." On these lectures this book is based.
It may also be regarded as a revised edition of my similar work, published in French, entitled, "La Mathematique des Jeux" ("The Mathematics of Games").· The present book is, in fact, better than a revised edition, since during nine of the intervening years (1931-1939) I was editor of Sphinx, a periodical devoted to recreational mathematics. This experience has made it possible to bring many improvements and much new material to the work.
Many individuals and organizations have assisted in making it possible for me to write this book. It is my grateful duty to thank them. If the reader likes this book he is in debt to those listed below:
The United States of America, which, by opening its doors for me, has deserved no small part of my thanks.
Mr. D. Heineman, who made it possible for me to come to this country, which is now the refuge of so many scientists of distressed Europe.
Dr. Alvin Johnson, Director of the New School for Social Research, who made it possible for me to bring before an American audience the results of my researches.
Mr. Donald A. Flanders, who has not only helped me to adapt the expression of my thoughts to an unfamiliar idiom, but has throughout embellished the book with the results of his own reflections. Some of the material on magic squares is due to him, particularly the methodical use of lattices; and many other pages have benefited by his explanations.