Calculus of Friendship

Steven Strogatz is the Jacob Gould Schurman Professor of Applied Mathematics at Cornell University. His books include the best-selling "Sync: The Emerging Science of Spontaneous Order" (Hyperion). He has written for the "New York Times"'s Opinionator blog.

"An intimate view of mentorship is revealed by US mathematician Steven Strogatz in The Calculus of Friendship, a compilation of letters exchanged with his high-school math teacher over 30 years. Through their correspondence they share problems in calculus, chaos theory and major life events, from professional and sporting successes to family bereavements and divorce. The book touchingly charts their changing roles and relationship, from student to professor, teacher to retirement."--Nature "The spring of his freshman year in college, Strogatz began to exchange letters with his high school calculus teacher, Don Joffray. At some point, their amiable correspondence about math problems led to a true friendship. In The Calculus of Friendship, Strogatz weaves their letters into reflections on the philosophical similarities between calculus and human relationships and portrays a friendship firmly founded on a love of dreaming up and solving calculus problems ... One can also feel the personality and humor of these pen pals emerging through their symbol-sprinkled sentences."--Science "Part biography, part autobiography and part off-the-beaten-path guide to calculus, this quick read details 30 years of correspondence between Strogatz and Joffray. Calculus, Isaac Newton's ingenious invention for modeling change mathematically, serves as both text and subtext for the letters that pass between Strogatz and Joff. Focusing almost exclusively on questions of mathematics, these brief notes frame the unlikely friendship of a teacher and his star student. With the precision of an award-winning mathematician and the clarity of a best-selling science author, Strogatz leads us on an excursion through some of the lesser-known mathematical sights--the ones usually reserved for the 'members only' tour... The mathematics covered in these letters is impressive for such a short volume."--American Scientist "There is no better English-language explicator of complex quantitative concepts than Steven Strogatz. His work is a model for how mathematics needs to be popularized."--Michael Schrage, Harvard Business Review "This story will draw in both the novice and the veteran. Teachers of mathematics will appreciate the long-term effect their teaching can have on students. The included mathematics can be related to both high school and undergraduate calculus sequences to demonstrate some interesting, thought-provoking, and 'big picture' connections to these courses."--Mathematics Teacher "[A] beautiful book, bound to become a classic in the mathematical literature... Like Hardy's A Mathematician's Apology, you don not have to know any mathematics whatsoever to read this book. It is a candid and all-too-human story told with brutal honesty, warts and all, sharing with the reader the elation and sincere regrets bound up in the relationship--but in the end, the victories, too. With some beautiful mathematics throughout!"--Lawrence S. Braden, Notices of the American Mathematical Society "You wouldn't guess it from the title, but The Calculus of Friendship is a genuine tearjerker. I defy anyone to follow the correspondence between mathematician Steven Strogatz and his high school teacher Don Joffray (affectionately nicknamed 'Joff') without getting just a little lachrymose. If you don't, check to see if there is a heart in your chest. If there is, ensure that it's not just a cold slab of stone."--Bookslut "The story of the correspondence between these two men is at once charming and subtly powerful. Strogatz writes directly and honestly, telling the story of a slow-growing friendship that was at once somewhat stilted and yet deep and sustaining. The immediacy and intimacy of Strogatz's writing transform the pleasures and tragedies of normal life into the elements of a compelling narrative, and because the book works so well on this human level, it also very effective in presenting some important lessons about education and about mathematics."--Mathrecreation blog

• Prologue ix Continuity (1974-75) 1 Pursuit (1976) 8 Relativity (1977) 13 Irrationality (1978-79) 23 Shifts (1980-89) 34 Proof on a Place Mat (March 1989) 42 The Monk and the Mountain (1989-90) 71 Randomness (1990-91) 84 Infinity and Limits (1991) 94 Chaos (1992-95) 107 Celebration (1996-99) 115 The Path of Quickest Descent (2000-2003) 118 Bifurcation (2004) 128 Hero's Formula (2005-Present) 140 Acknowledgments 155 Further Reading 157 Bibliography 161 Photography Credits 163 Index of Math Problems 165