The life of the American humorist (1902-71) as he cleverly related it through letters, most of them to the muse he met at a Baltimore dinner dance. ""This is a peculiarly gifted and intelligent pen. Look what it's writing now: I love you."" Witty and romantic, Nash's early letters document his three-year suit for ""Miss Leonard,"" which he won in 1931, the year his first book of light verse, Hard Lines, became an instant best seller. Evocative social documents, these letters reveal Nash as a love-struck Cyrano, a playful poet, but also as a detached editor. They crackle with tales of the publishing business and its personalities--Edna Ferber, Dorothy Parker, Harold Ross, and Nash's boss ""Old Mr. Doubleday,"" who held meetings in his yellow Packard ""some thirty feet long"" driving from Rothman's, ""the wettest spot on [Prohibition] Long Island."" In the book's second half, ""The Family Years,"" Nash's stream of funny poems (""I hope I never learn what flesh/I ate today in Marrakech"") and devoted letters reveal him as the creator of his daughters' ""magic"" childhood of roomy houses and summers by the sea. The eldest, Linell Nash Smith, who here selected Nash's letters and, in introductions, describes the private side of his life, claims she ""had no idea"" that her ""gentle, unassuming"" father was a ""household word"" until, at age 11 (in 1943), she went to the opening of his Broadway hit One Touch of Venus. Unfortunately for the reader, Nash's later letters shield the family from his troubles (like the struggle to repeat his theatrical success) and his doubts about the relevance of humor ""in a world gone mad."" Even in extravagantly ""loving"" letters, Nash keeps the distance of a humorist controlling the gates to his inner sanctum--a stratagem to order a serious modern life as carefully as he ordered his nonserious poems. In sum: many wise punch lines.