Continuing in the tradition of earlier editions, and orange serves as the theme for the front cover of this 4th edition. The orange, a product of nature, represents a common but complex assortment of chemicals, including many examined in this textbook: surcrose, which gives the orange its sweetness (Ch. 16), citric acid, which provides a bit of tartness (Sec. 10.8), the cellulose of its pulp (Sec. 16.11), the water of its fluids (Sec. 3.13), and its ascorbic acid, more commonly known as vitamin C (Sec. 19.6). Crystals of this same vitamin C, illuminated by polarized light, appear in a striking microphotograph on the back cover. This photograph reveals the remarkable nature of even the most common things of our daily lives. Taken together, the images of the front cover and the back cover represent the range of the ordinary and extraordinary things of our everyday lives that are described simply but in detail between these two covers.Snyder, Carl H. is the author of 'Extraordinary Chemistry of Ordinary Things', published 2002 under ISBN 9780471415756 and ISBN 0471415758.