If someone wants to know what astronomers do, or geologists, or ecologists, or cell biologists--that someone being a high school teenager or a parent--one can think of no more charming introduction than Bonner's book. He is an eminent biologist and a good writer and here he presents a distillation of the major fields of science, arranged, of all things, by size places. He starts out with big astronomy, moves on to geology, then to ecology and population genetics. From many people the logical step is to single individuals and then to smaller subunits, getting down to cells, macromolecules, atoms, and elementary particles, which of course, winds up full circle because what are the workings of stars but the machinations of nuclear particles. There is just enough information to give you meat, enough philosophical insight to make you realize that there is something to this size ordering which is related to man's perception and also to such concepts as time and motion, and just enough tease, in terms of current research and unsolved problems, to incite the imagination.