Buckley's week is intriguing - ego and all

William F. Buckley's Cadillac is two feet longer than everyone else's. Tuna fish is one of his favorite lunchtime dishes. Money, for Buckley, is not in short supply.

Do I care?

Oddly enough, yes. There is something unexpectedly winning about Buckley. In his latest book, Overdrive: A Personal Documentary (Doubleday, $16.95), he name-drops unashamedly. (Ronald Reagan is an old friend; Barbara Walters asks for his advice; David Niven was a favorite weekend guest.) He has the gall to serve up a 102-word sentence. Add to that his obvious relish in what seems an overwhelming arrogance - he is in fact proud of his pride.

All these things (plus 101 others) would irritate me in anyone else. But not in William Buckley. His zest for words, his obvious devotion to his craft, and perhaps even his quiet assumption that we do care about his thoughts and his deeds win me over.

''Overdrive'' takes us through a typical week in the life of America's most articulate conservative, editor of The National Review, host of the talk show ''Firing Line.''

He tells us about the thoughts that occur to him as he goes about his daily work and play, drives to his office, answers his mail, goes to the theater, advises the President.

He includes a fascinating reprint from the New York Times about his school days, reminds us of his proposal that ''all young people graduating from high school be encouraged to give a year's time to helping to care for the aged,'' and teaches me a new word that I particularly like.

I am proud to add ''antonomasia'' to my vocabulary. The dictionary describes it as a term for the kind of verbal currency exchange that occurs when someone refers to a judge as ''his honor'' or to a philanderer as a ''Don Juan.'' It's a device that, when misapplied, once cost Buckley $5,000 in an out-of-court settlement for libel.

And so I sit with Buckley's book on my lap, and feel I am listening to half a conversation, as Buckley follows up train after train of thought. Most of what he has to say is fascinating; once in a while it is memorable.

Here, for instance, is an important warning: Referring to John Kenneth Galbraith, a friend at the opposite end of the political spectrum, Buckley writes that the liberal economist is ''entirely convinced that the Lord has provided man with a fundamental apparatus by which we distinguish between what is right and what isn't; and convinced that the challenge to right thought and right conduct was never in history more menacingly threatened.''

These convictions may be Galbraith's; they are certainly Buckley's.