Once, a reader wrote a wild letter to William F. Buckley, Jr., condemning him for all manner of failure, not excluding "lousy syntax." Buckley answered tersely: "If you had my syntax, you'd be rich."

Buckley himself is rich, and not only because of family money: His syntax is a wonder. It is also his alone. In an age of literary homogenization, Buckley is instantly recognizable. You glance at a single sentence -- a clause, even -- and you know that it is Buckley.

Who else would write that something is "as well known as that Coca-Cola is the pause that refreshes"? Who else would begin a column, "If you're looking for a handy way to curb the population explosion, try the death penalty for anybody who asks, 'Do the ends justify the means?'" Who else would observe that, when a dull statesman addresses a gathering, "all the birdies stay perched on the trees"?

Buckley, now just past 70, has spent a lifetime with words. He edited the magazine he founded, National Review, for 35 years; he has written a syndicated column since 1962; and he is the author of almost 40 books, 11 of them novels. Along the way, he has had much to say about language, and certain of his admirers had hoped that, in the twilight of his career, he might find a week or two to produce his Fowler's.

Now someone has gone and done it for him. Buckley: The Right Word is the brainchild of Samuel S. Vaughan, Buckley's

The book offers chapters on such subjects as usage, vocabulary, letter- writing, fiction, reviews, and eulogies (a Buckley specialty). It is engaging on the small questions (Who or whom?) and on the large ones (What gives English its unequaled expressive power?). It includes piquant examples of Buckley's speeches, columns, interviews, and correspondence. Particularly entertaining, and instructive, is a lengthy exchange between Buckley and the critic Hugh Kenner on the following Buckley sentence:

Robert F. Kennedy had a way of saying things loosely, and it may be that that is among the reasons why so many people invested so much idealism in him, it being in the idealistic (as distinguished from the analytical) mode to make large and good-sounding generalities, like the generality he spoke on April 5 after the assassination of Martin Luther King, two months exactly before his own assassination.

The sentence is not Buckley's best, but he defends it unyieldingly, assuring Kenner that he would not put him "to such inconvenience merely for my own amusement." Buckley is generous in matters of language, as in others. In a remembrance of New Yorker editor William Shawn, he smarts at Shawn's criticism of his (idiosyncratic) use of the comma, saying, "If Saint Peter had declared me unfit to enter the Kingdom of God, I could not have felt more searingly the reproach . . ."