A muckraking exposÃ‰ of the founder of the Jewish Defense League. Friedman, a contributing editor to the Village Voice and sometime correspondent in the Middle East, first interviewed Meir Kahane in 1979 and last in 1984, but interviews with others bring his account up to the present. With a nose for the sordid, Friedman traces Kahane's life from a troubled childhood through rabbinical school--where his academic record was less than outstanding--and on to his eventual removal to Israel. The ""FBI informant"" in the title comes from the fact that Kahane tried to whip up enthusiasm for the Vietnam War on college campuses and allegedly tried to infiltrate the John Birch Society; the F.B.I. denies he was ever on their payroll. Kahane's first and only congregation was a small conservative synagogue in Queens. There he did very well with the youth (Friedman considers Kahane's one positive attribute to be inspiring the young), but his ultraorthodox views eventually compelled the congregation to ask him to leave. From that point on, it was politics only for Kahane. In 1968, he founded the Jewish Defense League; but after the group became linked with a number of violent and illegal actions, Kahane moved to Israel. He ran for the Knesset on three successive occasions, and, in 1984, he was finally elected. Since his sole contribution to political thinking was to suggest that all Arabs be expelled from Israeli soil, the Knesset and the Israeli courts found him and his party to be racist, and dismissed him from the Knesset. He still resides in Israel. The Jewish Defense League broke up years ago in the US, and Kahane has no hope of reentering the Knesset. The reader, at this late date, may find it difficult to share Friedman's great alarm at the Kahane phenomenon.