It would be too simplistic to classify David Letter­man as a talk show host, or his programs as fitting neatly into the talk show genre. Still, the format for both Late Night and Late Show resembles the familiar late night scenario. An opening monologue by the host usually plays off the day's news or current events. The monologue is followed by two or three guests who appear individually and chat with the host for five to ten minutes. Before and between the guest appearances, the host might indulge in some comedic skit or specialty bit. Despite their similarity to this basic format, however, Letterman's shows differ from others in the areas of program content, delivery, and rapport with guests.

     The content of both Late Night and Late Show has remained remarkably steady over the years. Standard installments included "Viewer Mail," which became "The CBS Mailbag" after the move. During this segment, Letterman reads actual viewer letters and often responds to requests or inquiries with humorous, scripted video segments featuring Shaffer and himself. Another long-time Letterman bit is "Stupid Pet Tricks," in which ordinary people travel to the program and showcase pets with unusual talent. In one sequence Letterman hosted a dog that would lap milk out of its owner's mouth, and from that bit sprang "Stupid Human Tricks." In this segment people present unusual talents such as tongue distortion and spinning basketballs; one man vertically balanced a canoe on his chin. One of the most popular elements in Letterman's repertoire is the "Top Ten List." Announced nightly by Letterman, this list-"express from the home office in Sioux City Iowa"-features an absurdly comic perspective on current events and public controversies.

     Other specialty bits have included sketches such as "Small Town News," during which Letterman reads goofy or ironic headlines from actual small town newspapers, and "Would You Like To Use the Phone?" in which Letterman invites a member of the studio audience to his desk and offers to place a phone call to someone he or she knows. Letterman sent his mother, known to fans as "Letterman's Mom," to the 1994 Winter Olympics in Lillehammer, Norway, where she interviewed First Lady Hillary Clinton and skater Nancy Kerrigan for the Late Show. Letterman frequently visits local businesses near his Broadway theater: the copy shop, a local cafe, and a gift shop run by "Mujibar and Sirijul," two brothers who have become quite famous because of their visits to the show and their performances in skits on the program.

     Letterman's style melds with the content of his program, both often unpredictable and out of control. His delivery is highly informal, and like the content, the personal performance is extremely changeable, given to sudden outbursts and frequent buffoonery. This style builds on the carefully constructed persona of "a regular guy," and Letterman often "wonders" with the audience just how a guy like him managed to become the host of one of the most popular late night shows in America. He has referred to himself as "the gap­ toothed monkey boy" and frequently calls himself a "dweeb" (which his band leader Shaffer usually acknowledged as true). This "regular guy" excels at impromptu delivery and the ability to work with his audience. He often hands out "gifts and prizes" such as light bulbs, motor oil, and most notably, his trademark brand "Big Ass Ham." He has been known to send his stand-by audience to Broadway shows when they were not admitted to his taping. Letterman's relationship with his studio and viewing audiences does not always translate to his treatment of his guests, however.

     Over the years of Late Night and Late Show, Letterman has hosted first ladies, vice presidents, film and television stars, national heroes, sports figures, zoo keepers, wood choppers, six-year-old champion spellers, and the girl next door. His relaxed attitude can make guests feel at home, and he can be a very gracious host if he so chooses. But there have been time5 when he has offended guests (Shirley MacLaine nearly hit him) and been offended by guests (Madonna offended the nation with her obscene language and demeanor on one of her visits with Letterman).

     Perhaps the most significant moment in Letterman's career to date occurred in the aftermath of the September 11 attacks on the World Trade Center and the Pentagon. In what was viewed by some as an attempt to return to "normalcy," Letterman returned to his late night spot on Monday following the attacks. Somber, at times apparently stalled with emotion, he cited Mayor Rudolph Giuliani's admonition for New York­ers to return to work and hosted guests Dan Rather and Regis Philbin. Rather twice broke into tears during their conversation, and Philbin revealed that his son had been at work in the Pentagon, though on the opposite side of the plane crash, on the 11th. Late Night with David Letterman was, on this occasion, something of a significant cultural marker for many viewers, an indication that late night television comedy could be the locus for powerfully shared moments c,f cultural significance.

     Early in 2002, as Letterman's contract with CBS was set to expire, rumors circulated that the show would move to ABC, as a replacement for the news program Nightline, hosted by Ted Koppel. Letterman was re­portedly unhappy with CBS, particularly with the local­ news lead-ins it used. However, in March of 2002, Letterman did indeed renew his contract with CBS.