Cullings from the ""Missing Links"" column that paleontologist Khrishtalka writes for a bimonthly Carnegie Institution magazine. A tendency toward sophomoric humor mars the reliable and often insightful information here: ""Did dinosaurs perform bizarre mating rituals? Dinosaurs were by nature into leather. . .""; a column largely devoted to the ""extinction"" or ""extirpation"" of baseball teams; lists of legitimate definitions that start off with jokes, e.g., ""ideal gas--The kind of gas that used to cost 25 cents a gallon."" Otherwise, the range of material is interesting, if familiar: the Piltdown hoax; the current dinosaur controversies; origins of Homo sapiens; conjectures over cave paintings; creation myths (including the Mother Eve hypothesis); intelligent life in the universe; the diet of early man; squabbles over taxonomy, and the like. For the most part, Krishtalka's point of view is orthodox--critical of dinosaur doom theories and lashing out at Fred Hoyle and colleagues for calling Archaeopteryx fossils forgeries (and thus providing grist for creationists' mills). There are some personal chapters concerning the badlands and sites where Krishtalka has dug, including the sad tale of the Big Horn saloon in Arminto, Wyoming--once the lively turf for bone-hunters, moosehunters, oilmen, and sheepherders, and now burned down. Other chapters deal with calendars, metric measure, and other matters of time and space. Useful overall, more so for newcomers who don't mind bad puns.