Who is Bill Gray from Mao II and what is their importance?

Gray is the character around whom the action of the narrative (with the exception of the Prologue and Epilogue) revolves. After becoming internationally renowned, critically acclaimed, and academically studied following the publication of two novels, he withdrew from public life and became something of a hermit, or recluse. Events of the narrative are initiated, triggered, and/or defined by his emerging, increasingly irresistible desire to return to the world, with initial attempts focusing on the photographs he arranges to have taken or talk of publishing the new novel he keeps endlessly revising. Events of the narrative suggest, however, that both these two possibilities feel, to Bill, unsatisfactory. It's only when editor/publisher Charles Everson offers him the opportunity to take a public position against terrorism that he finds himself emotionally engaged in his re-emergence, there being the sense that the first two attempts were good ideas, nothing more - nothing passionate, nothing personal, nothing truly real.