Veteran true-crime author Graysmith (Zodiac, Unabomber, etc.,) weighs in with an ambitious theory linking the Ripper killings with two murders committed in San Francisco in the spring of 1895. Graysmith's Ripper is John George Gibson, a Canadian-born Baptist preacher who resigned his parish in Scotland in 1887 and whose whereabouts are unknown until his arrival in the U.S. in December 1888, a month after the last Ripper murder. Although a medical student was convicted and hanged for the San Francisco murders, Graysmith makes a persuasive argument that only Gibson had the time and access to kill the two women, whose bodies were found in his new parish, the Emmanuel Baptist Church in San Francisco's Mission District. His own detailed drawings and diagrams of the labyrinthine church further his case. However, Whitechapel enthusiasts will find much to refute Graysmith's contention that Gibson was the Ripper. The San Francisco victims were not prostitutes; there was none of the careful mutilation that marked the Ripper as a man with some medical training; and the killer didn't boast to the authorities of his crimes. The book itself is gratuitously detailed, padded with too many diversions about the battle between newspaper tycoons Mike de Young and William Randolph Hearst, as well as with long biographies of the writers and artists who covered the slayings. As it stands, only devoted followers of the Ripper murders will remained interested to the end. (Aug.) FYI: Touchstone Pictures is making a film of Zodiac.