I do all my writing by dictation into tape recorders,"" says versatile Steve Allen. . . and his new book reads that way: these 18 profiles of comedians are rambling mixtures of facts, anecdotes, tributes, insights, clichÃ‰s, repetitions, irrelevancies, and downright nonsense--plus transcripts of interviews, comics' routines, etc. Woody Allen gets the longest treatment, in a 30-page piece that combines sincere praise with much deadly analysis (""I have made separate paragraphs of the individual, component building blocks of the story, to enable the reader better to see precisely where it is that the laughs fll. . .""); moreover, both the Woody profile and one on Mel Brooks seem obsessed with their (admittedly important) Jewishness, which leads to many stale, dub ous generalizations about Jews and a few bizarre interpretations of non-Jewish jokes. Somewhat better balanced are discussions of offbeat Steve Martin (who basically ""imitates jerks""), often-boring Andy Kaufman, and erratic Richard Pryor--whose ""combination of rudeness and irresponsibility. . . is not merely a separate character weakness. . . but is literally tied up with his talent."" And there are brief sketches of such others as George Burns, Jimmy Durante, G. Marx (""The Groucho I revered was the ad-libber in private life""), Lily Tomlin, Robin Williams, Peter Sellers (mostly a TV-appearance transcript), Bill Cosby, and--with the most personal affection--Sid Caesar and Jonathan Winters. Some of Allen's inside knowledge fills out the personalities here; sometimes, as when memories of Lenny Bruce are interrupted for a tribute to Allen's wife Jayne Meadows, the effect is only self-indulgent. Still, though readers will be disappointed if they're looking either for Allen's on-camera humor or for fresh commentary, passionate fans of the comedians involved may find this a painless, quasi-serious potpourri.