Nonplussed!, as the title suggests, is a marvelous study of some two dozen choice mathematical problems that boggle the mind. Unlike so many books on recreational math, Havil doesn’t hesitate to give crystal-clear proofs and their necessary equations. John Conway’s great checker-jumping puzzle is here, along with amazing nontransitive betting paradoxes and other confounding results almost impossible to believe. No one interested in recreational mathematics on an intermediate advanced level should pass up this stimulating, delightful volume. –Martin Gardner In Nonplussed!, his new book of fascinating discussions of mathematical questions, Julian Havil’s literary signature is evident even without seeing his name on the cover. The presentation always displays his strong ability to weave together the historical with what is often a surprising mathematical twist, even for those problems that have been around long enough to be called classic. Nonplussed! will be a classic, too. –Paul J. Nahin, author of Dr. Euler’s Fabulous Formula Nonplussed! ! is a very interesting and eclectic mix of paradoxes that has the potential to be a very useful and lasting contribution to popular mathematics. –Christopher J. Sangwin, author of Mathematics Galore I greatly enjoyed this book and I imagine that anyone who liked high school math will too. Nonplussed! certainly succeeds in surprising-and in giving insightful proofs of the mathematical results discussed. It is a magnificent demonstration of how far even rather straightforward mathematics can take you. And by describing many of the historical characters involved and the problems that motivated them, it makes mathematics seemlike an adventure. –Nick Huggett, author of Space from Zeno to Einstein