The super-patriots who out-Birch the Birchers here get carefully unbiased treatment. Somewhat gabby conspirators, the Minutemen admit to hording guns and ammunition, mailing hate literature, and training their cadres in techniques of guerrilla warfare and espionage. So far, they say, their ""psy-war"" has not mushroomed to violence. But the FBI says differently, and currently some half dozen Minutemen are under indictment for allegedly blowing up four banks. The group's two top leaders, Robert Bolivar DePugh and Wally Peyson, are being sought on related weapons charges. The trials, possibly late this year, may spark interest in the book. The author is a Kansas City Star reporter who has been covering the Minutemen for five years. His chatty, chronological account is drawn from taped interviews, beer sessions, his experience on a police raid of Minuteman headquarters, and his own five-year perspective. The group has supplied him with ""for-members-only"" material. In return, the author provides a serious assay and one apt horselaugh: ""Where else, without sending in box tops to a cereal company, can someone obtain his very own secret code number and mail drop and then be asked to keep suspected Communists in his city under surveillance?