Fiction: Where fiction and biography overlap there lies a new genre - fictive biography. Or should that be biographical fiction? Whatever you want to call it, the novel based on a real person's life has certain constraints and huge liberties.
The novelist usually has a documented life as raw material, but can leap off imaginatively when the facts let him down. So what advantage does the novelist have over the biographer when it comes to the lived life? Well, the obvious advantage is that he can invent; the second is that he can dramatise.
Comedian Bert Williams, the subject (rather than the main character) of Caryl Phillips's latest novel would seem to offer much in the drama department. Caribbean by birth - like Phillips himself - Williams emigrated with his family to the US in the late 1880s. He was academically bright enough to be considered for Stanford University but family circumstances dictated another route; at 16 he joined a travelling medicine show.
It was the first step in a journey that ended up with him being the highest-paid entertainer of his time and to be regarded by WC Fields as "the funniest man I ever saw, and the saddest man I ever knew". When he partnered up with George Walker, the pair toured lumber camps and vaudeville theatres the length and breadth of the US, and by the turn of the century they were headlining on Broadway.
Two events sealed Williams's uncomfortable fate as a performer. One was a decision made in Detroit in 1896 to swap roles with Walker. Though the more serious and introspective of the two, he became the clown to Walker's straight man. The other decision - more troubling entirely - was to "black up" in order to play a "shuffling, dull-witted, clumsy, watermelon-eating Negro of questionable intelligence".
The irony was that Williams was West Indian and not African-American. "As he looked at himself in the mirror the predicament was clear - but just who was this new man and what was his name? Was this actually a man, with his soon-to-be-shuffling feet and his slurred half-speech and his childish gestures and his infantile reactions? Who was this fellow? Sambo? Coon? Nigger? However, the audience never failed to recognise this creature. That's him. That's the nigger!"
This is familiar territory for Phillips, himself an emigrant twice over - born in St Kitts, brought up in Leeds and now resident in the US. Though his other novels - particularly A Distant Shore, about the burgeoning of friendship between a young Sierra Leonean man and a retired white music teacher - appear to be about race, it is, in fact, identity that intrigues Phillips as a writer. And the strongest passages in this novel are when Phillips, in his cool reflective prose, contemplates the faultlines created in Bert Williams's life by his own masquerades.
For it is Williams's loss of authenticity by playing the stage black man that both seals his great success and informs his emotional decline. The comedian married but the marriage was not a happy one. Phillips, the biographer, suggests this was a sexless union and very early on in the piece Bert takes to referring to his wife, Lottie, as "Mother". But Phillips, the novelist, fails to explore this emotional black hole at the heart of Bert Williams's life. This reader was shouting from the stalls - look behind you! Cherchez la maman! Are we to believe that Williams's career was his only true passion or that so great was the rupturing of his identity - first by migration, then by the adoption of a mask - that he couldn't allow sexual intimacy to fragment it any further? The biographer may halt at the bedroom door but the novelist must barge right in.
It is this failure to inhabit Bert Williams that makes Dancing in the Dark such a frustrating read. His dilemma is decoded intellectually, he is made to stand in for the intelligent man who knowingly plays the fool, but he never comes alive as a novelistic creation. Phillips has carefully researched his novel, and the period detail is fascinating.
The intertextual use of newspaper cuttings and show scripts gives us a kaleidoscopic view of the rackety world of vaudeville and the wonderful anarchy of turn-of-the-century New York society. But essentially, Dancing in the Dark is more careful reconstruction than imaginative reinvention and we, as readers, are left hovering at the stage door hoping against hope for an unguarded glimpse of the star turn.
Mary Morrissy is a novelist. She is researching her next novel at the New York Public Library, where she was awarded a fellowship at the Dorothy and Lewis Cullman Center for Scholars and Writers
Dancing in the Dark By Caryl Phillips Secker and Warburg, 214pp, £12.99