RETURN OF THE COMET MAN: REVIEW

In ''I Been There Before,'' the mind-boggling apparatus is so accurately reproduced that the book is all but indistinguishable from the real thing. But is this the only intent? Scholarly sendups have their fascination, as do pastiches, but this is a novel, or so the title page says, and Mr. [David Carkeet] is the author of two previous novels, ''Double Negative'' and ''The Greatest Slump of All Time.'' Does the book transcend the limitations of parody and pastiche, and bring to life not just [Samuel Langhorne Clemens] the man and [Mark Twain] the writer but the other characters: the book's actual narrator, Frederick Dixon, the putative general editor of the Mark Twain Papers; his renegade note-taking sidekick, Ricky Olivieri; Umlauf the Usurper; Cocoa and her Extraordinary Twins; Herman the German, better known as the Twain Man? As Frederick Dixon hopefully suggests in his preface, is the evidence ''so overwhelming that no sooner does one dip into it than the question 'Did he really come back?' quickly gives way to questions like 'When did he go up in the Transamerica Pyramid?' and 'Did he fly to New Orleans first-class or coach?' ''? WELL, almost. If Mr. Carkeet's reproduction of critical apparatus is mind-boggling, his imitation of Mark Twain's literary voice (and Samuel Clemens's personal one) in the various stories, sketches and letters, including the ones that Clemens aspires to write in the ''modern style'' of objective narration, is nothing short of dazzling. It's Frederick Dixon's increasingly perplexed and perplexing narrative entitled ''On the Trail of Samuel Clemens'' - following each of the three sections by the returned Mark Twain - that raises the problem of suspension of disbelief.