A very good, well-written popular survey of representative egg-laying vertebrates as developmental phenomena on the evolutionary scale, with emphasis on methods of reproduction. The author, a scientific journalist, has his sights on adaptive movement and change through the millennia -- from the notochordal (forerunner of the spinal column) sea lancet up through the nesting bird, and he thoughtfully provides the novice with a chapter on classification, as an aid to an orderly view of the phylum Chordata. Stivens then reviews primitive sea creatures like lampreys, sharks (with their cartilaginous skeletons), that ""uncle"" of land dwellers, the lungfish, and the many kinds of bony fishes -- those that protect their eggs by burying them, building nests, holding them in their mouths, etc. The amphibians receive, not surprisingly, a great deal of attention since they evolved the ""basic body plan of land-dwelling vertebrates"" -- a four-limbed body, spine, limb girdles, etc. But it was the reptilian egg that ""made possible the conquest of the land by reptiles, birds and then mammals,"" and Stivens discusses some ""living fossils"" and others of more modern derivation. He devotes a chapter to snakes, a few of which brood their eggs like birds, while others bear their young alive. The largest section of the book concerns birds -- of reptilian ancestry but warm-blooded and able to develop a high metabolism. There are discussions of territorial and mating procedures, the composition of the egg, nest building, care of the young, incubation. Along the way the author points out how the structures of eggs answered the survival problems of major vertebrates. As an example of everything-and-nothing-in-particular is a concluding profile of that ever-popular dingbat duo -- the duckbilled platypus and the other primitive mammal, the spiny anteater. Far less scrambled than Bourne's survey of the primates (see above).