How we grow; and what happens when mistakes occur Mutants is a book about how the body develops and grows from a single cell to an adult and then declines into old age. What does the new molecular genetics tell us about the human condition? How is a limb formed? Why do we have five fingers (and not six)? What controls the size to which we grow? Why do we age? More than this, however, it is a brilliant narrative history of what happens when things go wrong. This book tells, rather like a biological verison of The Man Who Mistook His Wife for a Hat, the stories of particularly historically important and bizarre cases: of a French convent girl of the last century who found herself changing sex upon puberty and her miserable fate in the gutters of Paris; of children, invariably stillborn, who have cylopia (one eye located beneath their nasal cavity); of a tribe of pygmies in the Andaman Islands and a village of Ecuadorian dwarves: of a remarkably hairy family who were kept at the Burmese Royal Court for four generations (and from whom Darwin took one of his keenest insights into heredity); and so on. From each important lessons are drawn that illustrate over and over again the amazing nature of cellular growth and how it works.