An illuminating biography of one of the greatest geometers of the twentieth century Driven by a profound love of shapes and symmetries, Donald Coxeter (1907–2003) preserved the tradition of classical geometry when it was under attack by influential mathematicians who promoted a more algebraic and austere approach. His essential contributions include the famed Coxeter groups and Coxeter diagrams, tools developed through his deep understanding of mathematical symmetry. The Man Who Saved Geometry tells the story of Coxeter’s life and work, placing him alongside history’s greatest geometers, from Pythagoras and Plato to Archimedes and Euclid—and it reveals how Coxeter’s boundless creativity reflects the adventurous, ever-evolving nature of geometry itself. With an incisive, touching foreword by Douglas R. Hofstadter, The Man Who Saved Geometry is an unforgettable portrait of a visionary mathematician.

"There is perhaps no better way to prepare for the scientific breakthroughs of tomorrow than to learn the language of geometry." -Brian Greene, author of The Elegant Universe The word "geometry" brings to mind an array of mathematical images: circles, triangles, the Pythagorean Theorem. Yet geometry is so much more than shapes and numbers; indeed, it governs much of our lives-from architecture and microchips to car design, animated movies, the molecules of food, even our own body chemistry. And as Siobhan Roberts elegantly conveys in The King of Infinite Space, there can be no better guide to the majesty of geometry than Donald Coxeter, perhaps the greatest geometer of the twentieth century. Many of the greatest names in intellectual history-Pythagoras, Plato, Archimedes, Euclid- were geometers, and their creativity and achievements illuminate those of Coxeter, revealing geometry to be a living, ever-evolving endeavor, an intellectual adventure that has always been a building block of civilization. Coxeter's special contributions-his famed Coxeter groups and Coxeter diagrams-have been called by other mathematicians "tools as essential as numbers themselves," but his greatest achievement was to almost single-handedly preserve the tradition of classical geometry when it was under attack in a mathematical era that valued all things austere and rational. Coxeter also inspired many outside the field of mathematics. Artist M. C. Escher credited Coxeter with triggering his legendary Circle Limit patterns, while futurist/inventor Buckminster Fuller acknowledged that his famed geodesic dome owed much to Coxeter's vision. The King of Infinite Space is an elegant portal into the fascinating, arcane world of geometry.

An illuminating biography of one of the greatest geometers of the twentieth century Driven by a profound love of shapes and symmetries, Donald Coxeter (1907–2003) preserved the tradition of classical geometry when it was under attack by influential mathematicians who promoted a more algebraic and austere approach. His essential contributions include the famed Coxeter groups and Coxeter diagrams, tools developed through his deep understanding of mathematical symmetry. The Man Who Saved Geometry tells the story of Coxeter’s life and work, placing him alongside history’s greatest geometers, from Pythagoras and Plato to Archimedes and Euclid—and it reveals how Coxeter’s boundless creativity reflects the adventurous, ever-evolving nature of geometry itself. With an incisive, touching foreword by Douglas R. Hofstadter, The Man Who Saved Geometry is an unforgettable portrait of a visionary mathematician.

How can we be sure that Pythagoras's theorem is really true? Why is the 'angle in a semicircle' always 90 degrees? And how can tangents help determine the speed of a bullet? David Acheson takes the reader on a highly illustrated tour through the history of geometry, from ancient Greece to the present day. He emphasizes throughout elegant deduction and practical applications, and argues that geometry can offer the quickest route to the whole spirit of mathematics at its best. Along the way, we encounter the quirky and the unexpected, meet the great personalities involved, and uncover some of the loveliest surprises in mathematics.

An instant New York Times Bestseller! “Unreasonably entertaining . . . reveals how geometric thinking can allow for everything from fairer American elections to better pandemic planning.” —The New York Times From the New York Times-bestselling author of How Not to Be Wrong—himself a world-class geometer—a far-ranging exploration of the power of geometry, which turns out to help us think better about practically everything. How should a democracy choose its representatives? How can you stop a pandemic from sweeping the world? How do computers learn to play Go, and why is learning Go so much easier for them than learning to read a sentence? Can ancient Greek proportions predict the stock market? (Sorry, no.) What should your kids learn in school if they really want to learn to think? All these are questions about geometry. For real. If you're like most people, geometry is a sterile and dimly remembered exercise you gladly left behind in the dust of ninth grade, along with your braces and active romantic interest in pop singers. If you recall any of it, it's plodding through a series of miniscule steps only to prove some fact about triangles that was obvious to you in the first place. That's not geometry. Okay, it is geometry, but only a tiny part, which has as much to do with geometry in all its flush modern richness as conjugating a verb has to do with a great novel. Shape reveals the geometry underneath some of the most important scientific, political, and philosophical problems we face. Geometry asks: Where are things? Which things are near each other? How can you get from one thing to another thing? Those are important questions. The word "geometry"comes from the Greek for "measuring the world." If anything, that's an undersell. Geometry doesn't just measure the world—it explains it. Shape shows us how.

Among the many beautiful and nontrivial theorems in geometry found in Geometry Revisited are the theorems of Ceva, Menelaus, Pappus, Desargues, Pascal, and Brianchon. A nice proof is given of Morley's remarkable theorem on angle trisectors. The transformational point of view is emphasized: reflections, rotations, translations, similarities, inversions, and affine and projective transformations. Many fascinating properties of circles, triangles, quadrilaterals, and conics are developed.

Geometry is brought to life as Euclid explains principles of Geometry to his friends. With jokes and lots of illustrations, discover the beauty of geometry and, before you know it, you too will soon be a friend of Euclid! Shoo Rayner adds humour and simplicity to a tricky subject. A perfect introduction.