Seinfeld is a television sitcom, considered to be one of the most popular and influential of the 1990s in the U.S., to the point where it is often cited as epitomizing the self-obsessed and ironic culture of the decade. In 2002, TV Guide released a list of the 50 best TV shows of all time and ranked Seinfeld #1. The show stars Jerry Seinfeld playing a character named after and based largely on himself, and is set predominantly in an apartment block in Manhattan's Upper West Side, New York. It features an eclectic cast of characters, mainly Jerry's friends and acquaintances – Cosmo Kramer (Michael Richards), George Costanza (Jason Alexander) and Elaine Benes (Julia Louis-Dreyfus). It is produced by Castle-Rock Entertainment (then helmed by famed actor and producer, Rob Reiner) and is distributed by Columbia Pictures Television (now Sony Pictures Television).

The show has been famously described as "the show about nothing", as most of the comedy was based around the largely inconsequential minutiae of everyday life, often involving petty rivalries and elaborate schemes to gain the smallest advantage over other individuals. The characters have also been described as utterly selfish and amoral, and to a degree that is accurate; the show stands out in deriving nothing but amusement from it. (However, it should be noted that a common motif concerns characters' attempts to do nice little things for people, only to have everything backfire exponentially in the face of the person who tried to do right.) Unlike other sitcoms, when a moment was just about to lapse into sentimentality, it managed to regain its balance. Jerry Seinfeld and Larry David's dictum of "no hugs, no learning" gave the show its distinctively cold and cynical tone. However, themes of illogical social graces and customs, neurotic and obsessive behavior, and the mysterious workings of relationships ran in numerous episodes, making it possible to categorize the show as a comedy of manners. The show is also unique in reflecting the activities of real people, rather than the idealized escapist characters often seen on television, although many episodes do feature surreal escapades, often based on scenes from famous movies.

Originally called "The Seinfeld Chronicles", the initial plot of the series was to tell how a comedian got his material, hence, the insertion of clips of Jerry Seinfeld's routine. The clips became less and less frequent as the series progressed partly due to the show focusing more on its characters rather than on the initial "How a comedian gets his material" plot. However, this was never the true intent of the show. Jerry Seinfeld and Larry David used it only in their pitch to NBC. Also, in the pilot Kramer was originally called Kessler and had a pet dog. Elaine wasn't even supposed to be a main character. One of the waitresses at the restaurant was supposed to have the female recurring role.

Previous shows on television were almost always family or co-worker driven, and Seinfeld holds itself up as being a then-rare example of a sitcom wherein none of the characters were related by blood or employed, if at all, in the same building or business.

According to Bruce Fretts' 1993 The "Entertainment Weekly" "Seinfeld" Companion, Seinfeld's audience was, "TV-literate, demographically desirable urbanites, for the most part-who look forward to each weekly episode in the Life of Jerry with a baby-boomer generation's self-involved eagerness." Likewise, in episodes adhering to the original concept, the show featured clips of Seinfeld himself delivering a standup routine at the beginning and end of each episode, the theme of which relates to the events depicted in the plot. By this device the distinction between the actor Jerry Seinfeld and the character who is portayed by him is deliberately blurred. In later seasons, these standup clips became less frequent. All the main characters were modeled after Seinfeld's nonfictional acquaintances.

Another violation of the fiction convention of isolating characters from the actors playing them, and separating the characters' world from the actors' and audience's world, was a story arc that concerned the characters' roles in promoting a television sitcom series named Jerry. Jerry was much like Seinfeld in that Seinfeld played himself, and that the show was "about nothing". Jerry was launched in the 1993 season premiere of Seinfeld, in an episode titled "The Pilot". This story arc, along with other examples of self-reference, have led many critics to point out the postmodern nature of the show.

According to Katherine Gantz, this entanglement of character and actor relationships "seems to be a part of the show's complex appeal. Whereas situation comedies often dilute their cast, adding and removing characters in search of new plot possibilities, Seinfeld instead interiorizes; the narrative creates new configurations of the same limited cast to keep the viewer and the characters intimately linked. In fact, it is precisely this concentration on the nuclear set of four personalities that creates the Seinfeld community".

Another attribute that makes Seinfeld exceptional is that in almost every episode, several story threads are presented at the beginning, generally involving the various characters in separate and unrelated situations, which then converge and are interwoven towards the end of the episode in an ironic fashion. Due to the densely-plotted construction of the storylines, attempts to summarize the action in a given script are generally more verbose than one would expect for a sitcom. Despite any separate plot strands, the narratives show "consistent efforts to maintain [the] intimacy" between the small cast of characters. "Much of Seinfeld's plot and humor hinge on outside personalities threatening—and ultimately failing—to invade the foursome, ... especially where Jerry and George are concerned."

Gantz maintains that another factor in, or further proof of, spectators' and characters' participation in a Seinfeld community is the large amount of in-slang, "a lexicon of Seinfeldian code words and recurring phrases that go unnoticed by the infrequent or 'unknowing' viewer". These include Snapple, Bubble Boy, Cuban cigars, Master of My Domain, Junior Mints, Mulva, Crazy Joe Davola, Pez, Sponge Worthy, and Vandelay Industries.

The show premiered on May 31, 1990 on NBC. Seinfeld was not an immediate success. After the pilot was shown, on July 5, 1989, a pickup by NBC did not seem likely and the show was actually offered to Fox, which declined to pick up the show. It was only thanks to Rick Ludwin, head of late night and special events for NBC, for diverting money from his budget, that the next four episodes were filmed. After nine years on the air and 180 episodes filmed, the series finale of Seinfeld aired on May 14, 1998. It was watched by a huge audience, estimated at 76 million viewers. Jerry Seinfeld holds both the record for the "most money refused" according to the Guinness Book of World Records by refusing an offer to continue the show for 5 million dollars per episode, and another record for the Highest Ever Annual Earnings For A TV Actor[1] (http://www.guinnessworldrecords.com/index.asp?id=47798), while the show itself holds the record for the Highest Television Advertising Rates

In the UK Seinfeld was screened on BBC TWO, usually at around 11:30 PM. Fans and critics constantly campaigned for an earlier time slot, but it never happened. The show was subsequently rerun on the Paramount Comedy Channel on satellite in a mid-evening slot.

In 2004 a deal was negotiated to make Seinfeld available on DVD for the first time. Due to legal problems with the cast involving episode commentary and other DVD extras, the release was pushed back. The first 3 seasons were released November 23, 2004. The DVD packaging claims that the series was remastered on HDTV to provide the best possible picture quality.