When David Letterman performed his first set on The Tonight Show on November 24th, 1978, did he imagine he'd one day be angling for the job being vacated by Johnny Carson? Hard to know, but there's a lot in his performance that feels like Letterman, host and future late-night personality. The comedian's high-brow smarts, his evocative writing ability, his wry silliness, his willingness to push an audience's buttons all factor in here. In the set, he talks about those things he knows — cars, planes and the media, in particular — while teasing out his own sense of the absurd. One thing on Letterman's mind is a tabloid headline that claims to help you lose weight without a diet or exercise: "Pretty much leaves disease, doesn't it? 'I was able to lose over 60 pounds without diet or exercise. What's my secret? Well, I was lucky enough to be seriously ill for about a year and a half.'" Interestingly, Letterman doesn't kill with the in-house audience, but there's clearly enough of his warmth and personality inherent in his act to get him a foothold with Carson.