Gift ideas -- choicest new books for the holidays; Natural history; The National Museum of Natural History, by Philip Kopper. Photographs by Kjell Sandved and Chip Clark. New York: Harry N. Abrams. 496 pp. $60.

With the publication of this marvel of illumined text and full-color photographs, all the tourists who've had only a couple of days to spend sightseeing in the nation's capital can heave a collective sigh of relief. Now they can settle back for as long as they like to get to know each collection of this Smithsonian museum in detail. It's all here, from visual close-ups of starry gems and seashells, to wry musings about the museum's more bizarre exhibits and researchers, to behind-the-scenes glimpses of how chemists, anthropologists, and beetles (yes, beetles!) work together to produce some of the most stunning and most realistic displays in the world.