Emerald City is an extremely controlled environment, with a carefully managed balance of members from each racial and social group, intended to ease tensions among these various factions.

Under McManus and Warden Leo Glynn, all inmates in "Em City" struggle to fulfill their own needs.

Others, corrections officers and inmates alike, simply want to survive, some long enough to make parole and others just to see the next day.

There are the African-American Homeboys (Wangler, Redding, Poet, Keane, Adebisi) and Muslims (Said, Arif, Khan), the Wiseguys (Pancamo, Nappa, Schibetta, Zanghi, Urbano), the Aryan Brotherhood (Schillinger, Robson, Mack), the Latinos of El Norte (Alvarez, Morales, Guerra, Hernandez), the Irish (The O'Reilly brothers, Kirk, Keenan), the Gays (Hanlon, Cramer, Ginzburg), the Bikers (Hoyt, Sands, Burns), the Christians (Cloutier, Coushaine, Cudney) and many other individuals not completely affiliated with one particular group (Rebadow, Busmalis, Keller, Stanislofsky).

In contrast to the dangerous criminals, central character Tobias Beecher gives a look at a usually law-abiding albeit alcoholic man who made one fatal drunk-driving mistake.

Oz took advantage of the freedoms of premium cable to show elements of coarse language, drug use, violence, frontal nudity, homosexuality, and rape of males, as well as ethnic and religious conflicts that would have been unacceptable to traditional advertiser-supported American broadcast television.

[8] On April 21, 2009, Variety announced that starting May 31, DirecTV will broadcast all 56 episodes in their original form without commercials and in up-scaled "high definition" on The 101 Network available to all subscribers.

In Croatia, Estonia, and Slovenia, the show was aired late at night on public, non-commercial, state-owned channels HRT, ETV, and RTV SLO, respectively.

The first season of Oz has been ranked a 70 based on the rating aggregator website Metacritic, indicating generally favorable reviews by critics.

[14] Caryn James from The New York Times stated: "Set almost entirely in the prison, a high-tech horror with glass-walled cells, Oz can also be unpleasant to watch, it is so gruesome and claustrophobic.

The point of Oz, with its depiction of guilty men in torturous circumstances, is never subtle, but it is complicated and strong.

Frederic Biddle of the Boston Globe said: "A pretentious exercise in cheap thrills, by great talents allowed to run amok.

"[17][18] Howard Rosenberg of the Los Angeles Times reported: "Its uniqueness and arresting style don't earn it an unqualified endorsement here, for its first two Fontana-written episodes are absolute downers--there's no light at the end of a tunnel, nor even a tunnel--that offer no central characters to like or pull for...Be forewarned, too, that Oz is flat-out the most violent and graphically sexual series on TV.