It takes one to know one. Among the accomplished memory artists of The Company They Kept: Writers on Unforgettable Friendships (New York Review Books), edited by Robert B. Silvers and Barbara Epstein, are Saul Bellow on John Cheever, Anna Akhmatova on Amedeo Modigliani, Derek Walcott on Robert Lowell, Elizabeth Hardwick on Mary McCarthy. Whether fond or surprisingly frank (Susan Sontag disliked Paul Goodman as much as she valued him), these essays are soothing in their intimacy, their acceptance of fallible fellow humans. "As always," writes Robert Oppenheimer of Albert Einstein, "the myth has its charms; but the truth is far more beautiful."