On the morning of Aug. 27, 1883, the volcano Krakatoa, situated in a group of small islands between Java and Sumatra, erupted with such force that it sent tremors both physical and otherwise around the world. Calculated to have been the fifth most powerful volcanic blast in history, it killed, according to the official count, 36,417 people, most by the gigantic ocean waves it set in motion. It was the first world-altering eruption to occur after the invention and spread of the telegraph and, thus, the first to be studied and profiled with scientific exactitude from all points of the globe. How the volcano came into being and what its explosion has meant to humanity is the story Simon Winchester tells in his new book Krakatoa. Whether he is tracing the evolution of the Oxford English Dictionary, as he did in The Professor and the Madman, or detailing how England's geological foundations were first charted, as in The Map That Changed the World, Winchester's specialty is putting important historical events into a wider context. His context here may seem a bit too wide, however, taking into its leisurely embrace such diverse arcana as plate tectonics, ancient and modern shipping routes and Javanese social organization under Dutch colonization. It takes the author more than 200 pages to get to the actual eruption. But for readers who savor data and anecdotes as Winchester so clearly does, the wait will be worthwhile. Winchester is just as far-ranging when tracing the effects of the eruption. He credits it with everything from influencing the style of certain landscape painters to being a factor in the rise of Islamic fundamentalism in Indonesia. (And he makes persuasive arguments for both.) "Here was the event," he writes, "that presaged all the debates that continue to this day: about global warming, greenhouse gases, acid rain, ecological interdependence. Few in Victorian times had begun to think truly globally even though exploration was proceeding apace, the previously unknown interior of continents were being opened for inspection, and the developing telegraph system, allowing people to communicate globally, was having its effects. Krakatoa, however, began to change all that."The 1883 explosion was so massive that the volcano cone destroyed itself and slipped beneath the surface of the sea. In 1930, though, it began to re-emerge and has since grown into a respectably-sized island now rich in plant and animal life. Winchester concludes his book with a first-hand description of the place that once wrought such havoc and which may someday do so again.