Acknowledgments

For the last five or six years I planned a volume similar to this one, but life circumstances in each case stalled the project before completion. The breakthrough came after a fortuitous conversation with Steven Strogatz in the fall of 2009. From there I consulted closely with Vickie Kearn, the Princeton editor of the book. She is the perfect collaborator on such a project, and every time I use the third person pronoun “we” in the introduction I refer to Vickie just as much as to me. Thanks also to Vickie’s assistant, Stefani Wexler, for her efforts to obtain many reprinting permissions.

In finalizing the content I benefited from several suggestions offered, once again, by Steven Strogatz and Vickie Kearn, and one by Aaron Weinberg. Thanks to all other people who have seen the table of contents and opined on it. I also thank the contributors who made available their original figure and photo files. Useful comments made by anonymous reviewers contributed to the final content of the introduction; I am thankful to them. Of course, the responsibility for the shortcomings in the final result is entirely mine.

The staff at the Cornell University Libraries (particularly the Mathematics Library) were always kind and expedient in ordering materials not immediately available.

Many thanks to the people who assigned me adequate teaching and research duties over the last few years, especially David W. Henderson and Maria Terrell—but also Katherine Gottschalk, Paul Sawyer, Stanley Seltzer, Richard Durrett, Elise West, Sarah Hale, and Carol Shilepsky. Directly or indirectly, they made it possible for me to work on this book.

I thank Kristen Grace and Brendan Wyly for indirect support, in difficult personal circumstances for me.

Finally, I thank my daughter, Ioana Emina. She accompanied me to libraries, sometimes patiently but more often impatiently, making sure that we did not spend too much time in a noise-free environment. Her cheerful indifference to my scrupulousness in tracing books and periodicals helped me put my task in proper perspective. I dedicate this book to her.