The concept of function determining form that helped to focus Patent's The World of Worms (1978) is central to this stimulating review, which considers different body systems in terms of the job to be done: getting here and there, delivering vital materials, and so on. Patent starts out with a look at the paramecium, which even within its one cell has specialized parts to perform the same basic functions that are handled by the more sophisticated systems investigated later. Early on, she goes into the importance of surface volume ratio, which then helps to answer such questions as ""why do water animals get so much larger than land ones?""--and, later, to explain variations in animals' digestive tracts. Patent has a way of making a sense of phenomena in nature (citing, for example, the ""good reasons"" for male animals' coloration and females' drabness) and she disarms with questions kids might consider too dumb to ask: ""How does water from the roots get all the way up to the top [of a 300-foot redwood tree] when the tree has no 'heart' to pump it up?"" In her bibliography Patent cites a Stephen Jay Gould column on animal sizes and shapes, and her readers will be well prepared for Gould; adapting her own form to her more elementary function, she offers the same sort of intellectual pleasure.