This is an entertaining introduction to the development of numbers and their applications. The book is written in the same user-friendly style that characterises the author s previous books. It blends easy material with more challenging ideas about infinity and complex numbers and is full of interesting examples ranging from recreational puzzles to very real world scenarios. There are historical notes which give the mathematics context and short digressions while a final chapter For Connoisseurs provides the mathematical detail for those who would like to know more about the questions and techniques highlighted. The book will appeal to anyone who is curious about the mathematics behind real-life questions. It will inspire and motivate those thinking of studying mathematics at university and will provide invaluable material for teachers and lecturers.