The law, justice Holmes once said, is the calling of thinkers. Very few lawyers fill that bill. Thurman Arnold did.

Arnold was always a little larger than life. His career spanned active duty in World War I to Wyoming lawyer, mayor of Laramie, dean of the West Virginia Law School, professor of law at Yale, author of best sellers, head of the Antitrust Division in the Department of Justice, judge on the U.S. Court of APpeals, founding partner of a superior corporate law firm, to his death in 1969. Not bad, not bad at all.

Professor Gressley of the University of Wyoming chose several hundred of Arnold's letters - those written by, not to, him - from some 17,000. They give the flavor of a remarkable man, one who would have stood out anywhere but who was a rara avis in a profession noteworthy for circumspection and dullness.

Thurman Arnold was not always right, as in his defense of the Vietnam misadventure and his overblown faith in the legal process, but no one could misunderstand where he stood. My first memory of him came when we participated in a conference in the early '60s. Someone was droning on about economic theory. Finally, arnold could stand it no longer. He rose, got the chairman's attention, drew on his cigar, growled that "economics is theology," and stomped out of the room. He was right to do so.

Now, more than ever, we need the Thurman Arnolds of the world. A city of nameless and faceles technocrats requires people with his pungent wit and incisive language.

Whoever knew him, whether well or only slightly, as I did, will read these letters with appreciation.Others will catch a part of a courageous and intelligent man.

The book is marred by many typographical errors and Gressley's failure to update it - in his introduction and notes. The introduction, tracing Arnold's life, suffers from being a bit breathless in tone. But those are minor flaws. (Colorado Associated University Press, $15)