Solid science writing and appealing acrylic, watercolor, and chalk illustrations combine to convincingly tell the incredible story of how a furry, four-legged land creature, the mesonychid, evolved into the modern whale. McNulty (A Snake in the House, 1994, etc.) concisely details the millions of years of evolutionary changes, from a ""walking whale"" (ambulocetus) to the ""hardly walking whale"" (rodhocetus), and finally, to the more recent whale, the dorudon. For each change the author describes, based on fossil evidence, the body adaptations, probable diet, and life cycle of the creature. The accompanying paintings, covering two thirds of each spread, capture the splendor of ancient animals known only from fossils and from the features of the contemporary whale. Although the text appears entirely in uppercase, which fussily detracts from the clear, accessible writing, this is an exceptional title.