In the last year of his Nixon watch Osborne has come to resemble an old bulldog worrying a much chewed bone. We must be grateful for his tenacity; alone among the White House press corps he consistently pushed for insights into the private Nixon. Even now, in an overview prepared especially for this collection of his New Republic columns, Osborne has an answer of sorts for those who are still wondering why Nixon didn't just bum the damn tapes at the beginning. (Apparently he wanted to and was dissuaded by the more cautious -- or cocky -- Haldeman.) Osborne also zeros in on Nixon's neurotic preoccupation with detail as revealed in Alex Butterfield's testimony and suggests, with support from an unnamed presidential staffer, that the Boss has been going harmlessly crackers for some years. Unfortunately those who will be most eager to believe this are equally likely to find Osborne himself annoying and tendentious. He admits to a residual awe of the imperial presidency. . .and even of Nixon whom he persists in characterizing as ""that saddening and extraordinary man."" Given Osborne's sentimental belief that ""people who cherished little dogs couldn't be all bad"" and his regret at not having revealed to the world the stirring fact that Nixon wore reading glasses, one might well be suspicious of his weekly assessments which contend, by turns, that Nixon was/was not confident of exoneration and was/was not falling to pieces. Certainly Osborne can be gullible, yet -- on the off-chance that they didn't catch these columns the first time round -- there's just enough here to satisfy the diehard Nixon watchers. Paul Szep's trenchant Boston Globe cartoons are an extra.