A view of Rome, a pristine computer screen, a photograph of Basquiat, an I.B.M. 196c typewriter, the ghost of another author. For these writers — each of whom releases a new book this fall — all they need to inspire is within these walls. JONATHAN LETHEM The study at the author's summer house in Blue Hill, Me., where he is a co-owner of the used-book store Red Gap. Lethem’s “Dissident Gardens” (Do