They weren't the original bad boys -- Humphrey Bogart's Rat Pack of nocturnal revelers came before Frank Sinatra's -- but they were the famous ones: Sinatra, Dean Martin, Sammy Davis Jr., Joey Bishop, Peter Lawford and a host of hangers-on and wannabes, male and female. In Las Vegas, a city that really did never sleep, and in Hollywood, where they teamed up in matinee movies highlighted by the original Ocean's Eleven, they cut quite a swath through the '60s: a martini-fueled "adult" answer to the Beatles and all else that was happening. LIFE was there to document all of the fun and frolic. John Dominis was sent out on the Sinatra beat, and grew to know and appreciate the singer, an avocational photographer who eventually allowed Dominis into his world -- the world of the Rat Pack. Dominis's hundreds of images are, today, something of an historical or sociological document. So many stars from so many spheres were at table with the core of "the clan" (as the boys actually called themselves): Shirley MacLaine, Jackie Gleason, Bing Crosby, President Kennedy, maybe the mob. They are all in this book, as are other Rat Pack intrigues: Sinatra expelling Lawford or Davis for perceived slights, the raucous hotel parties at the Sands and elsewhere. The sixties were swinging indeed when the Rat Pack was in town. In this volume, the Pack is back.