JUSTIN KAPLAN's prize-winning Mr. Clemens and Mark Twain brilliantly analyzed the dualisms inherent in one great, flawed American author. Whitman would seem an equally apt subject for Kaplan -- the more so since, half a life ago, he did the research for Louis Untermeyer's big Whitman anthology, published in 1949.

Much in his new book lives up to expectation. Kaplan remains an elegant stylist. He quotes copiously from Whitman yet often supplements and enhances. Whitman, for example, watches a train of just-demobilized Union soldiers disappear round a curve, so crowded that men cluster on the carriage roofs "like bees." Kaplan adds -- "agents of work, wealth and community." Sensitively alert to the writer's idiosyncratic powers, he also shows affectionate tact in dealing with Whitman the man. Kaplan resists the temptation to debunk, while not hiding the poet's less attractive aspects, such as his tireless plugging of Leaves of Grass, or his lack of enthusiasm for black Americans who did not happen to be runaway slaves.

There are shrewd comments on the post-Civil War publicity that Whitman or his disciples secured by portraying him as neglected and persecuted. Walt was, as Kaplan says, "renowned for the obscurity in which he supposedly languished." There are good remarks too on the evasions of this apparently most confessional of poets. Whitman covered his tracks and left false trails. Was the main reason a predominant homosexuality, which Whitman was impelled both to avow and to conceal? Kaplan handles the theme with discretion. He draws attention to certain lines of verse, and notebook entries, that defy a heterosexual reading. But such references stop short of redefining the Good Gray Poet as the Good Gray Poet.

On this level, however, the biography begins to disappoint. Graceful and fastidious, it is too inclined to be satisfied with "clues and indirections," to evoke instead of boldly hypothesizing. Dozens of scholars have after all already established the recoverable facts about Leaves of Grass, from the first edition of 1855 to the final 10th edition in 1892 (the year of Whitman's death) and about his own activities. The man and the work have been closely and repeatedly scrutinized. Significant new disclosures are unlikely.

The justification for another biography ought therefore to be that it grapples with the basic, important questions and offers convincing if speculative answers. For instance: Just how did Walter turn into Walt, the hack journalist evolve into the bard of the American Renaissance? Was his effort unique, or were others moving in the same direction? At one time or another Whitman's work received high praise from distinguished persons: Why then did he fail to win popular recognition? Is it possible that his contemporaries were right to distrust his mixture of the bizarre and the banal? Or that it was chiefly his sexual explicitness that offended? And, if so, that he could have met the objections by means of quite minor excision? Or did he perhaps protect himself from his failure with the American public through his very refusal to heed its taboos? Did the lack of popular acceptance not only bruise his ego but -- more profoundly -- challenge the soundness of his basic confidence in democracy? Why, though insisting upon his robust health, did Whitman also seem to welcome the onset of old age? Was there any true growth in his oeuvre after about 1865? Did he tend increasingly to confuse the Author with the Poem?

Justin Kaplan has obviously pondered such issues. They all figure in his book. But usually he is content to be allusive and brief. The last chapter tails off, almost as if he had got tired of Whitman. This may result from a shuffling of the chapter order: This may result from shuffling of the chapter order: The book so to speak begins at the end. One effect, though, is to blur the account of Whitman's later years, in particular the prose volume Specimen Days <(CONTINUED FROM PAGE 3) which, together with some surprisingly bland tributes to Longfellow, Tennyson et al, contains a remarkable meditation on the death of Carlyle -- for Whitman, a genius who had rejected democracy because he rejected mediocrity. Nor do we learn a great deal about the previous prose essay, Democratic Vistas, whose elements of Carlylean scorn consort oddly with hurrahs for the bourgeoisie.

We shall, or course, never know for sure how the writer of stuff like Whitman's 1842 temperance novel Franklin Evans: or The Inebriate levitated into the miraculous "Song of Myself." But I think Kaplan could have wrestled more with the problem. The literary and social context is somewhat conventionally sketched. (Is it true, by the way, that women of the 1850s wore nearly 100 yards of cloth apiece? This "fact" is offered without query.) American contemporaries such as Cornelius Mathews, who also had large literary ambitions, seem worth a mention; and the same hold even more for Melville and Longfellow, who are mentioned but whose endeavors could shed more light on Whitman. Verse experiments in England, for example by Martin Farquhar Tupper and Elizabeth Barrett Browning, could likewise be revealing -- not necessarily to show an influence upon Whitman, but rather an emanation of his Zeitgeist. Isn't Zeitgeist at work in Courbet's paintings -- big canvases depicitng ordinary people? One of them, L'Atelier, Leaves, and makes comparable attempts to identify the artist with a circle of friends, then more widely with the whole of mankind.

The arguement is not that Justin Kaplan was obliged to follow up any single specific notion of this type; but that en masse (as Whitman might have put it) there is not quite enough mass, enough originality, enough concern. What we have is a handsome narrative, invariably fluent and intelligent, but seldom astounding. Can it be that Whitman's influence insensibly pervades those who empathize with him, in some ultimate posthumous outreach of Whitmanic ego?