When plutonium was first manufactured at Berkeley in the spring of 1941, there was so little of it that it was not visible to the naked eye. It took a year to accumulate enough so that one could actually see it. Now there is so much that we don't know what to do to get rid of it. We have created a monster. The history of plutonium is as strange as the element itself. When scientists began looking for it, they did so simply in the spirit of inquiry, not certain whether there were still spots to fill on the periodic table. But the discovery of fission made it clear that this still-hypothetical element would be more than just a scientific curiosity - it could be a powerful nuclear weapon. As it turned out, it is good for almost nothing else. Plutonium's nuclear potential put it at the heart of the World War II arms race - the Russians found out about it through espionage, the Germans through independent research, and everybody wanted some. Now, nearly everyone has some - the United States alone has about 47 metric tons - but it has almost no uses besides warmongering. How did the product of scientific curiosity become such a dangerous burden? In his new history of this complex and dangerous element, noted physicist Jeremy Bernstein describes the steps that were taken to transform plutonium from a laboratory novelty into the nuclear weapon that destroyed Nagasaki. This is the first book to weave together the many strands of plutonium's story, explaining not only the science but the people involved.