Jack the Ripper and beyond--forty-one years in the investigative career of a man hailed by many as Scotland Yard's greatest detective of all time.   Fred Wensley was a Somerset gardener when he joined the Metropolitan Police in 1888. His first case was to unmask Jack the Ripper. At least it familiarized Wensley with Whitechapel, where he bided his time collaring less threatening ne'er-do-wells. After joining the CID, Wensley's career was a succession of triumphs. He brought to book the Bessarabian, Odessa, and Vendetta crime syndicates of London's East End; he played an instrumental role in smashing Latvian revolutionaries in the notorious Siege of Sidney Street; he formed the Flying Squad, a stealth surveillance team still operating to this day; and most infamous of all--his arrest in one of Great Britain's most notorious crimes of passion, a controversial cause célèbre that would shadow Wensley for the rest of his life.   Retired Flying Squad officer Dick Kirby has dug deep to paint a fascinating portrait of Fred Wensley, Chief Constable of the CID and the first recipient of the King's Police Medal, in this "welcome biography of a distinguished detective" (History by the Yard).