It's a huckstering idea, surely: for its 50th anniversary issue, Esquire commissioned 50 big-name writers (give or take a few everyday byliners) to profile 50 wave-making Americans of those five decades--individuals who, ominously, ""made a positive difference."" The results, expectably, are mixed: some token appearances (Norman Mailer apotheosizing ""Jackie the Prisoner of Celebrity,"" J. K. Galbraith commemorating ""Eleanor the Good,"" Kurt Vonnegut doodling about ""Jack the Dripper"" Pollock); some banal celebrations (Marilyn French on Betty Friedan, Alistair Cooke on Duke Ellington) and subjective meanders (most embarrassingly, Dotson Rader on ""The Last Years of Tennessee Williams""). But the surprise is the number of solid, reference-worthy pieces--full biographies or records-of.accomplishment--along with a handful of inspired, eclectic summations. At the head of any list of the informed and acute, full and balanced: John Updike on Edmund Wilson (a model of intelligent popularization); Robert Hughes on Alfred Barr, Arthur Schlesinger on Reinhold Neibuhr, Peter Drucker on Thomas Watson. Penetrating and nuanced: Murray Kempton on ""The Ambivalence of J. Robert Oppenheimer."" Sturdily reevaluative: Tom Wicker on LB J, Frances Fitzgerald on Earl Warren. An interesting apologia: George Leonard on ""Abraham Maslow and the New Self."" Among the imaginative reconstitutions are some dubieties and outright disasters--but also Max Apple's spanking essay on Walt Disney (which ends by juxtaposing Disney and Kafka as ""the bookends of the century""). The first-person testaments include Saul Bellow on FDR (""You didn't have to approve of Roosevelt's policies to be a Rooseveltian""), Arthur Miller on ""The Night Ed Murrow Struck Back,"" and David Bradley on ""Malcolm X, My Hero"" (as against ""prototypical New Negro"" Martin Luther King). Truman Capote relates a childhood brush with Katharine Hepburn that mightn't be true, but should be; James Salter manages not to be hackneyed about Ike. Some glaring omissions among the subjects--like George Balanchine--are only tacitly remedied by Elizabeth Hardwick's portmanteau chapter on ""The EmigrÃ‰s"" (one of three thematic pieces at the close). The omission of the New Yorker's Harold Ross seems a case of professional self-interest. (Also unrepresented are Clay Felker, the Village Voice and Roiling Stones strains; perhaps not sufficiently ""positive""--along with such missing Sixties persons as Bob Dylan, the political and culture radicals.) Lots of good writers are absent too, especially among the women. (Jane Jacobs, one feels, should have been here somewhere, either as author or subject.) But there is enough to pause over to be worth thumbing through, enough worth consulting to be worth the shelving.