Bus of My Own /A

When Lehrer was 12 years old, his family's inter-city bus company in Kansas went bankrupt, so as an adult the TV commentator and novelist has become an ardent collector of bus memorabilia, and he recently bought a 1946 bus. In this warm, unaffected autobiography tinged with the same irreverent humor that marks his One-Eyed Mack novels, Lehrer writes of life in the Marine Corps (``a ritual to manhood'') and of his 10 years as a reporter in Dallas, which taught him that murderers, sexual deviants and embezzlers have faces and families. Assigned to investigate the assassination of John F. Kennedy for two years, he deems both the lone-assassin theory and current conspiracy theories full of holes. Lehrer tells of his slow recovery from a heart attack and bypass operation in 1983, which prompted him to give up smoking. He defends the MacNeil/ Lehrer NewsHour against critics who fault its ``rabid evenhandedness'' and nonjudgmental approach. Peppered with anecdotes, this self-portrait limns a likable fellow who takes a daily nap, devours Georges Simenon novels and enjoys ``aimless driving'' through America's small towns. Photos. First serial to Reader's Digest; BOMC alternate; Reader's Digest Condensed Books selection. (Sept.)