Geochronology is the name of the game & Silverberg plays for high stakes--all or nothing: for the ordinary nonspecialist this will be a burdensomely comprehensive cumulative history of the theories that have been advanced about the human past, beginning with the most unrefined notions chained on pain of heresy to Genesis. Archbishop Ussher calculated the age of the earth arithmetically according to the bible. His figures were accepted almost until Darwinism opened up conceptual horizons & Smith's nomenclature yielded a primitive relative calendar. Some means of assigning absolute numerical values was still wanting when Becquerel stumbled on radioactivity & started the Atomic Clock ticking, but here's where the reader without considerable mathematical aptitude & stamina may turn off: Silverberg explicates the physical properties of the atom & the progressive discoveries of half-life, isotopes & the neutron, all of which must be assimilated if the breakthroughs & contingencies are to be appreciated. "Rutherford realized that the heat of radioactive decay would serve to keep the interior of the planet warm for a much longer time than the 20 million years Kelvin had estimated as the earth's age"; "radioactivity could supply a new & far more accurate figure for the age of the earth, if only a way could be found to measure the rate at which the decay of radioactive elements occurs." Indeed with more research ways were found for dating the earth's crust, the ice ages, evolutionary Homo Sapiens, archeological finds, even tree-rings--& the methods are many: lead-uranium, helium, zircon, rubidium-strontium, potassium-argon, carbon 14... For each method as for each application, we must go thru the procedural motions in detail, & not only where the technique is proved viable but also where (5 pages later, say) it's proved erroneous. Colloquially, this encompasses everything under the sun that admits of chronological measurement (see index); more meaningfully, it embodies both the sum & the substance of Silverberg's other works (see bibliography). An interdisciplinary study for the extra-disciplined inquirer.--Kirkus (edited)

The discovery of the remains of strange hairy elephants' that once roamed the temperate forests of Europe and America was an important link in the discovery of our own past. But what happened to them, and their position in the evolutionary ladder, is still an unsolved mystery.

As if history and nature had not provided wonders enough, through the ages humans themselves have contrived more marvels to deceive one another. Sometimes they have concocted evidence when none was available to prove pet theories; sometimes their intention has been to impress or defraud; sometimes they have acted merely for sport. ø Robert Silverberg tells the stories of a baker's dozen of these scientific hoaxers in a lively, good-humored book that ranges through time and across continents. Here are perpetual-motion machines and space rockets, men on the moon and serpents in the sea. The rogues? gallery is a varied one: Dr. Mesmer, who cast his hypnotic spell on eighteenth-century Paris; Charles Dawson, whose Piltdown Man challenged evolution; Dr. Cook, with his tale of ?discovering? the North Pole; and many others. ø These are fascinating stories and more than just entertainment. The author explains the scientific background against which the hoaxes appeared and the detective work that led to their exposure. The schemers teach us to be alert, to challenge the evidence, and to appreciate the healthy skepticism that characterizes the scientific method.