Möbius bagels, Euclid''s flourless chocolate cake and apple pi - this is maths, but not as you know it.In How to Bake Pi, mathematical crusader and star baker Eugenia Cheng has rustled up a batch of delicious culinary insights into everything from simple numeracy to category theory (''the mathematics of mathematics''), via Fermat, Poincaré and Riemann.Maths is much more than simultaneous equations and pr2 : it is an incredibly powerful tool for thinking about the world around us. And once you learn how to think mathematically, you''ll never think about anything - cakes, custard, bagels or doughnuts; not to mention fruit crumble, kitchen clutter and Yorkshire puddings - the same way again.Stuffed with moreish puzzles and topped with a generous dusting of wit and charm, How to Bake Pi is a foolproof recipe for a mathematical feast.*Previously published under the title Cakes, Custard & Category Theory*