As one of the few heavyweight comedians of Vegas's "Golden Age" to topline standup routines in 21st century Glitter Gulch - a time and place that saw him still reeling in massive audiences well into his 70s and 80s - Don Rickles qualifies as a show business legend. Rickles, of course, pioneered the use of insult comedy to mercilessly rib, skewer, and cut down to size anyone who happened to fall into his line of fire, earning him the sobriquets "Mr. Warmth" and "The Merchant of Venom" and lending a whole new meaning to the term "hockey puck." This approach, which seemed unprecedented and even outrageously uncouth in the late 1950s and early 1960s, eventually won Rickles legions of fans and innumerable protégés within show business - everyone from Richard Pryor to Chris Rock and Sarah Silverman. Director John Landis (National Lampoon's Animal House, Trading Places) stands at the forefront of Rickles's fan club and created the documentary Mr. Warmth: The Don Rickles Project as an homage to the comic's life and career. Landis intercuts footage from the Dean Martin Celebrity Roasts and Rickles's appearances on The Tonight Show with Johnny Carson, with extended clips from the shtickmeister's comedy routines and on-camera interviews in which the comedian reflects at length on his approach to comedy and journey through showbusiness. Admirers, colleagues and followers of Rickles also turn up to offer their views on the comedian - including Martin Scorsese, Christopher Guest, Robin Williams, Sarah Silverman, Sidney Poitier, Clint Eastwood and many others.