Official Definition of The DCAU (from the wiki):
The DC Animated Universe, or DCAU, is the name given to the shared continuity existing between the DC Comics-based animated series Batman: The Animated Series, Superman: The Animated Series, The New Batman Adventures, Batman Beyond, The Zeta Project, Static Shock, Gotham Girls, Lobo: Webseries, Justice League and Justice League Unlimited.
This continuity is also sometimes referred to as the Timmverse (after Bruce Timm, the continuity’s most consistent creative influence) and in the past, the Diniverse (after Paul Dini, who has mostly departed from Warner Bros.Animation).
Batman: The Animated Series (1992 – 1995; 1997-1999)
This animated series conveys the dark mood of the original “Batman” comic books. Unlike the light action “Batman” show of the 1960s, Gotham City’s Caped Crusader, Bruce Wayne, is sometimes moody. And Robin’s alter ego, Dick Grayson, has a more-mature personality than in the original series.
Batman: The Animated Series started the DCAU, and its virtually considered a must watch by all fans.
Essential Episodes: EW’s 25 Favorite Episodes List
Total Episodes: 85
Superman: The Animated Series (1996 – 2000)
Superman battles evil while trying to conceal his alter ego, Clark Kent.
Not the best of the DCAU, but lays the groundwork for the extended universe and connecting the threads of multiple shows together.
Essential Episodes, as I’ve garned from multiple sources: “The Last Son of Krypton,” “A Little Piece of Home,” “Stolen Memories,” “The Main Man,” “Tools of the Trade,” “Blasts from the Past,” “Speed Demons,” “Brave New Metropolis,” “Ghost in the Machine,” “The Hand of Fate,” “Prototype,” “Heavy Metal,” “Apokolips…Now”, “Little Lost Girl,” “Knight Time,” “New Kids in Town,” “In Brightest Day,” “The Demon Reborn,” and “Legacy.”
Total Episodes: 54
Batman Beyond (1999 – 2001)
Exciting adventures of a new Batman. Gotham is in desperate need of a new superhero to combat gangs.
A fun series, but ultimately not really necessary to the understanding of the DCAU, as its set in the future. There is an introduction to the Justice League though.
Essential Episodes: the pilot, “The Call,” “Out of the Past,” and the movie Batman Beyond: Return of the Joker
Total Episodes: 52
The Zeta Project (2001 – 2003)
A robot rebels against its creators, refusing to kill, and goes on the run.
Universally considered unnecessary, but die-hard fans might want to watch it.
Total Episodes: 26
Static Shock (2000 – 2004)
Accidental exposure to an experimental mutagen leaves geeky high school student Virgil with super powers. Able to control electromagnetic forces, he channels his newfound powers to fight evil, aided by his pal Osgood, who builds gadgets to help Virgil fight crime.
Another that most don’t feel is worth the effort to find and watch, though again, die-hard fans may want to.
Total Episodes: 52
Justice League (2001-2004)
The world’s greatest superheroes, including Batman and Superman, join forces to fight evil and ensure that justice prevails.
This one is a must watch! One of the best of the DCAU, though its a direct sequel to Superman: The Animated Series, so you may want to be previously familiar with those characters and stories.
Total Episodes: 52
Justice League Unlimited (2004 – 2006)
A continuation of the Justice League animated series finds the original members of the team joined in their battle against crime and evil by dozens of other heroes from the DC comics universe.
The last show of the official DCAU Continuity, and its a great one.
Essential Episodes: “Initiation,” “For the Man Who Has Everything,” “This Little Piggy” ; “The Greatest Story Never Told,” “Ultimatum,” “Wake the Dead,” “The Once and Future Thing” Parts 1 and 2; “The Doomsday Sanction,” “Task Force X,” “Double Date,” “Clash,” “Question Authority,” “Flashpoint,” “Panic in the Sky,” “Divided We Fall,” “Epilogue,” “Alive,” and “Destroyer.”
Total Episodes: 36
Total Episodes of the DCAU:
- Batman: Mask of the Phantasm (1993; theatrical release)
- Batman & Mr. Freeze: SubZero (1998; direct-to-video)
- Batman Beyond: Return of the Joker (2000; direct-to-video)
- Batman: Mystery of the Batwoman (2003; direct-to-video)