The purpose of a TV documentary, as is probably obvious from the genre's name, is to document something. Documentaries are non-fiction programs that examine a subject closely, and the intent of the program may be broadly educational, or it may attempt to make a cultural or political point. Although the earliest TV programming was focused on entertainment, documentaries quickly became a significant part of TV programming overall, and now some of the most popular TV networks concentrate almost exclusively on non-fiction programs. 562q4p

Documentary TV programming comes in a number of forms. Stand-alone documentary films explore one subject in depth in a single film or in a short series of episodes, while documentary series often look at a different subject in each episode, with no direct connection between the subjects from episode to episode. News-magazine-style shows may group multiple segments within each episode; the segments typically focus on unrelated subjects. Other types of documentary series-crime and paranormal series are currently popular-explore a different specific subject in each episode, but all of the subjects conform to the overall theme of the series.

Biography is a sub-genre of documentary programming that tells the story of a particular individual. Historical figures, political leaders, entertainers, sports figures and other celebrities are, of course, the most popular subjects of TV biographies, and biographical documentaries are consistently popular with TV viewers. In recent years, the series "Biography" was one of the most successful productions on the A&E cable network-so much so that the network spun the series off into its own channel, The Biography Channel, which debuted in 1999.

Much of the programming that fits into the reality TV genre could also fit fairly comfortably into the documentary genre. Reality series that follow characters as they engage in specific occupations or live in unusual contexts educate viewers about those occupations and lifestyles at the same time that they entertain-although the main goal of these series is entertainment, and factual accuracy may suffer as a consequence.