Batgirl is one of Batman's side-kicks and a member of the Batman Family similar to Robin. There have been several women to take the position over the years. The original Batgirl during the Silver Age was Betty Kane. This was later removed from continuity, and the character was reintroduced under the alias Flamebird. The most well-recognized Batgirl is Barbara Gordon, niece of Commissioner Gordon, and the original in modern continuity. She was Batgirl for many years until the Joker shot her through the spine during Killing Joke and paralyzed her. Barbara still fought crime from her wheel-chair as Oracle, an international super-hacker and invaluable computers expert for heroes everywhere. Helena Bertinelli, better known as Huntress, took the position during No Man's Land but later relinquished it. Cassandra Cain, daughter of the assassin David Cain, became the next Batgirl while seeking redemption for her father's crimes. She was eventually manipulated into going rogue by Deathstroke and gave up the cowl after she had recovered from her mental breakdown. The teleporter Misfit briefly called herself Batgirl when she started her vigilante career on the streets, although she changed her name after she was taken in by the Birds of Prey. Stephanie Brown, originally known as Spoiler and a former Robin, became Batgirl after the apparent death of Batman. Gordon has since returned to the position in the DCnU following a recovery.
Batgirl was created as Betty Kane by Bill Finger and Sheldon Moldoff, first appearing in Batman #139. (1961)
Barbara Gordon was created by Julius Schwartz, Gardner Fox and Carmine Infantino after a concept by William Dozier, first appearing in Detective Comics #359. (1967)
Helena Bertinelli first appeared as Batgirl in Batman: Shadow of the Bat #83. (1999)
Cassandra Cain was created by Kelley Puckett, Damion Scott and Alex Maleev, first appearing as Batgirl in Batman: Legends of the Dark Knight #120. (1999)
Charlotte Gage-Radcliffe started acting on her own as Batgirl in Birds of Prey #96. (2006)
Stephanie Brown took the position in Batgirl (Volume 3) #1. (2009)
Batgirl Volume 1 is Cassandra Cain's first solo title and the first ongoing book featuring a Batgirl character (formerly, Batgirl's adventures had been a backup feature in Detective Comics or special one-shot stories). It started publication in April, 2000 and was cancelled six years later.
Batgirl (Volume 2) was a limited series, published by DC Comics. It ran from 2008 until 2009. It starred Batgirl.
Batgirl is a DC Comics series written by Bryan Q. Miller, featuring Stephanie Brown in the title role. The series chronicles the adventures of Stephanie Brown, after she assumed the identity of Batgirl.
Batgirl (Volume 4) is one of The New 52 ongoing series published after Flash: Flashpoint, starring Barbara Gordon in the title role. While there were Batgirl ongoing comics before and Barbara Gordon's adventures were a backup feature in Detective Comics in the past, this is the first to feature Barbara Gordon in the title role. Previous series have featured Barbara in a supporting role and mentor to other Batgirls.
Barbara's time being paralyzed from the waist down is acknowledged and she resumes the costumed identity of Batgirl. At issue #35, the series is revamped with a lighter tone and a new status quo.
Batgirl (Volume 5) is an ongoing series, published by DC Comics. It began publication in 2016. It stars Batgirl.