After reading this gloomy exercise in futurology, even the most cockeyed optimists will feel justified in hiding under their bedcovers as the turn of the century approaches. Kennedy (History/Yale Univ.) explores again, with wider and more contemporary applications, a principal theme of his controversial bestseller, The Rise and Fall of the Great Powers (1987): that we must factor nonmilitary elements into traditional equations of national security. Kennedy can be provocative and prescient: his notion of ``global overreach'' in that earlier book, for instance, was borne out by the collapse of the Soviet Union and by the severe strains on the American economy. This time, he attempts to show how transnational forces, beyond the control of individual countries, inevitably will create world instability. Behind this unrest is a Malthusian population explosion (the world had 2 billion inhabitants in 1925, compared with 5.3 billion in 1990) that will be exacerbated by environmental dangers, the new global economy, robotics, and biotechnology. Kennedy guesses who the winners and losers will be in this changed world (Japan, with its highly educated, cohesive population and technological orientation, will fare better than the US, with its aging, multiethnic populace). Even the industrialized North will not be immune from the mass migrations and deteriorating environment of the Third World. Kennedy is most insightful in pointing out overlooked factors underlying crises: the fast-growing, youthful, impatient masses behind the Intifada and the troubles of Northern Ireland, for example, or the loss of forests and topsoil fueling the Haitian migration to the US. He regards economic growth as a zero-sum game that will damage an environmentally fragile planet, however, and he offers few remedies to avert the catastrophes he sees looming. Brilliant and discerning on the inevitable pressures on the rich North from the developing world (e.g., from Somalia)--but only hard-core Cassandras will accept Kennedy's pessimism about nations' inability to mobilize the will or resources to change the planet.