This much is known: Karen Silkwood, a young employee and union activist at the Kerr-McGee Nuclear Corporation plutonium plant, was found dead behind the wheel of her wrecked Honda off highway 74, south of Crescent, Oklahoma, in November 1974. She was on her way to Oklahoma City, to meet a New York Times reporter and deliver documents allegedly showing that Kerr-McGee had falsified its quality control and safety records. Less than a week before her death, Silkwood had been contaminated significantly by plutonium: she had eaten it and breathed it. In death, says investigative reporter Rashke, Silkwood became ""a nuclear martyr, a symbol to the feminists, the environmentalists, and the labor movement."" If this carefully researched account of Silkwood's death and its aftermath achieves nothing else, it succeeds at least in focusing our attention on facts, not rhetoric. Rashke is not a rabid antinuke, though he is skeptical of government regulations on ""safe"" contamination levels; nor is he engaged in a posthumous whitewash of Silkwood's image (yes, she took drugs; yes, she had a number of lovers), though he believes Kerr-McGee and the government indulged in gratuitous character assassination. What emerges is a reasonably balanced account of the facts of Silkwood's death, the ensuing congressional investigation, and the lawsuit brought by Silkwood's estate against Kerr-McGee for negligence in Karen's contamination which resulted in a $10.5 million recovery (now on appeal). Ironically, the courtroom victory came on a side issue; Silkwood's lawyers and investigators never put together enough pieces to prove their more frightening charge--that Kerr-McGee officials had conspired to harass and frighten Silkwood and other workers concerned about safety, and that the FBI had joined in a coverup of the illegal activity. They didn't fail for lack of trying, and the investigation led in some very strange directions (the CIA, for example) before time ran out. Rashke clearly believes Silkwood was murdered (the evidence is persuasive), but that's only the tip of the iceberg. By whom? And why? If she didn't contaminate herself, who contaminated her? Why? We may never have answers--one FBI source says it's all just ""buried too deep."" (Or, does the FBI know more than it's telling?) First-rate reporting and tight, edgy writing.