In May 2005 Penguin will publish 70 unique titles to celebrate the company's 70th birthday. The titles in the Pocket Penguins series are emblematic of the renowned breadth of quality of the Penguin list and will hark back to Penguin founder Allen Lane's vision of 'good books for all'. In this extract from Climbing Mount Improbable Richard Dawkins, bestselling author of The Blind Watchmaker, gives an introduction to evolutionary biology and unravels the mysteries of the highest peak of all: the eye.