Among the many constants that appear in mathematics, *π*, *e*, and *i* are the most familiar. Following closely behind is *y*, or gamma, a constant that arises in many mathematical areas yet maintains a profound sense of mystery.

In a tantalizing blend of history and mathematics, Julian Havil takes the reader on a journey through logarithms and the harmonic series, the two defining elements of gamma, toward the first account of gamma’s place in mathematics.

Introduced by the Swiss mathematician Leonhard Euler (1707-1783), who figures prominently in this book, gamma is defined as the limit of the sum of 1 + 1/2 + 1/3 + … Up to 1/*n*, minus the natural logarithm of *n*—the numerical value being 0.5772156… . But unlike its more celebrated colleagues *π* and *e*, the exact nature of gamma remains a mystery—we don’t even know if gamma can be expressed as a fraction.

Among the numerous topics that arise during this historical odyssey into fundamental mathematical ideas are the Prime Number Theorem and the most important open problem in mathematics today—the Riemann Hypothesis (though no proof of either is offered!).

Sure to be popular with not only students and instructors but all math aficionados, *Gamma* takes us through countries, centuries, lives, and works, unfolding along the way the stories of some remarkable mathematics from some remarkable mathematicians.

**Julian Havil** is a retired former master at Winchester College, England, where he taught mathematics for thirty-three years. He received a Ph.D. in mathematics from Oxford University. **Freeman Dyson** is professor emeritus of physics at the Institute for Advanced Study in Princeton. He is the author of several books, including *Disturbing the Universe* and *Origins of Life*.

"[A] wonderful book. . . . Havil's emphasis on historical context and his conversational style make this a pleasure to read. . . . *Gamma* is a gold mine of irresistible mathematical nuggets. Anyone with a serious interest in maths will find it richly rewarding."—Ben Longstaff, *New Scientist*

"This book is a joy from start to finish."—Gerry Leversha, *Mathematical Gazette*

"Wonderful. . . . Havil's emphasis on historical context and his conversational style make this a pleasure to read. . . .*Gamma*is a gold mine of irresistible mathematical nuggets. Anyone with a serious interest in math will find it richly rewarding."—*New Scientist*"A joy from start to finish."—*Mathematical Gazette*"[*Gamma*] is not a book about mathematics, but a book of mathematics. . . . [It] is something like a picaresque novel; the hero, Euler's constant*g*, serves as the unifying motif through a wide range of mathematical adventures."—*Notices of the American Mathematical Society*

"[*Gamma*] is enjoyable for many reasons. Here are just two. First, the explanations are not only complete, but they have the right amount of generality. . . . Second, the pleasure Havil has in contemplating this material is infectious."—*MAA Online*

"It is only fitting that someone should write a book about gamma, or Euler's constant. Havil takes on this task and does an excellent job."—*Choice*

"Mathematics is presented throughout as something connected to reality. . . . Many readers will find in [*Gamma*] exactly what they have been missing."—Mohammad Akbar, *Plus Magazine*

"This book is written in an informal, engaging, and often amusing style. The author takes pains to make the mathematics clear. He writes about the mathematical geniuses of the past with reverence and awe. It is especially nice that the mathematical topics are discussed within a historical context."—Ward R. Stewart, *Mathematics Teacher*

"I like this book very much. So much, in fact, that I found myself muttering 'neat stuff!' all the way through. While it is about an important topic, there isn't a single competitor. This amazing oversight by past authors is presumably the result of the topic requiring an author with a pretty sophisticated mathematical personality. Havil clearly has that. His skillful weaving of mathematics and history makes the book a 'fun' read. Many instructors will surely find the book attractive."—Paul J. Nahin, author of *Duelling Idiots* and *Other Probability Puzzlers* and *An Imaginary Tale*

"This is an excellent book, mathematically as well as historically. It represents a significant contribution to the literature on mathematics and its history at the upper undergraduate and graduate levels. Julian Havil injects genuine excitement into the topic."—Eli Maor, author of *e: The Story of a Number*