

Supergirl first appeared in 1959 in Action Comics #252, the same DC comicbook in which Superman debuted. She operated during the Silver and Bronze Ages (1) of superhero comics. Supergirl was Superman's cousin Kara from Argo City, Krypton (2). Her parents were Alura (spelled Allura in early stories) and Zor-El, Superman's uncle. "Sole survivor of the doomed planetoid which had hurtled away intact from an exploding Krypton - with a huge bubble of air conveniently attached - Supergirl crash-landed on Earth, just as her famous cousin originally had, after Argo City itself fell prey to deadly green-kryptonite radiation." (3) She had a red, yellow and blue uniform emblazoned with the family crest, a secret earthly identity (Linda Lee Danvers), and standard Kryptonian superpowers. Supergirl was only 15 when she first landed on Earth, but over the course of the next 25 years she would mature into a young adult and acquire a suprising amount of life experience. Although she was a teenager, she was never a teenage sidekick. Her adventures were her own. Superman was a distant authority figure who would visit from time to time during her high school years (while keeping obsessive tabs on her every move). But once she graduated and went off to college, she lived on her own with almost no adult supervision and generally operated independently.
The Great Superman Book (Michael L. Fleisher and Janet E. Lincoln, 1978, volume three in the The Encyclopedia of Comic Book Heroes) has this to say about Supergirl:
On Earth, like any Kryptonian survivor, she acquired super-powers identical to Superman's. Kara assumed the secret alternate identity of Linda Lee, an orphan at the Midvale Orphanage, concealing her blond hair beneath a brunette wig and functioning as Supergirl only in secret (at Superman's insistence) until 1962. She made her debut to the world in Action Comics #285. Adopted by Fred and Edna Danvers, she attended Midvale High School as Linda Lee Danvers, graduated in 1964, and then went on to attend Stanhope College on a scholarship, graduating in 1971.
Supergirl's alternate identity is a closely held secret, but it is known to Superman, to her foster parents the Danverses, and to the Legion of Super-Heroes, of which she served as a member until resigning her membership at the age of twenty-one. Supergirl is fully aware that her cousin Superman is secretly Clark Kent. Like all Kryptonian survivors, Supergirl is vulnerable to kryptonite. Comet the Super-Horse is Supergirl's pet and equine companion. Streaky, the orange cat that acquires temporary super-powers as the result of its exposure to 'X-kryptonite', is Linda Lee Danvers' pet cat.
Supergirl's early adventures in Action Comics are short, simple, and formulaic. The stories started becoming more complex and interesting during her college years, especially once she moved into her own book in Adventure Comics. The late sixties and early seventies marked a time of increased focus on character development and social issues in DC Comics, and while the results were mixed depending on the creative team, there was nothing dull about Supergirl's 70's run in Adventure, her own 10-issue Supergirl series, and her eight-year tenure in Superman Family. Kara had a very full career as Linda Lee Danvers: after graduating from Stanhope University with an unknown degree, she took a job as a camera operator and part-time journalist at a San Francisco TV station. Her working relationships at that job were certainly a challenge, especially with Lex Luthor's niece Nasthalthia "Nasty" Luthor there! A year later she went back to school as a grad student to study drama. Her next and longest position was as a student counsellor at a progressive high school - perhaps her undergrad was in social science? She made use of her drama training when she quit that job too (she always quit her jobs due to poor working conditions for some reason), upon receiving an offer to star in daytime television. Surprisingly, her last series had her returning to college once again, this time studying psychology. After 23 issues the second Supergirl series was cancelled, only a few months before her theatrical debut in 1984. DC intended to place Supergirl in another series, but someone in editorial must not have liked her, because she was shockingly killed off in the Crisis on Infinite Earths which herelded the end of so many female heroes. But Kara had far too strong a presence in DC comics to ever be forgotten.



In 1985, DC Comics ran a 12-issue crossover storyarc called "Crisis on Infinite Earths" which was designed to reduce the increasingly complicated DC superhero multiverse, which featured multiple versions of the same characters on Earth-1, Earth-2, etc. into a single, streamlined universe with one, revised timeline. Superman's story in particular was to be simplified. The multiple Earths were merged and many characters died and memories of them erased in the minds of the survivors. History was retroactively rewritten, and while some characters who died were remembered by those who survived the Crisis, all memories of Supergirl's existence were erased.
The Crisis was a critical turning point in all of DC's books, and is particularly important to Supergirl's history as it was the event in which she died. Published as both a hardcover and paperback oversized graphic novel. This is one book that DC Comics has kept in print over the years, as it redefined the entire DC Universe.
The previous Golden Age, Silver Age, and Bronze Age had all made changes to Superman's origin story and enhanced or reduced his abilities, but the Modern Age begun by Crisis was a complete reboot. In this new version of Superman, a DC company mandate stipulated that Superman be the sole survivor of Krypton with no relatives or superpets. There was no Supergirl from Krypton in this universe, and no one remembered Argo City. Yet the souls of those who had existed pre-Crisis were not destroyed. Supergirl's spirit lived on, perhaps to be reborn in another form.
A new Supergirl appeared just three years after Kara died, and in keeping with the revised Superman mythos, she was not biologically related to him. Her story starts in Matrix: A New Supergirl. Nearly twenty years after Kara's death and the rewriting of history, a reinvented version of the last daughter of Krypton was introduced to the post-Crisis universe: Kara II.
1. Supergirl debuted during the "Silver Age" of DC Comics and this original version of the character is frequently referred to as the "Silver Age Supergirl", although her 1970's-80's adventures took place during the Bronze Age. The first appearance of Superman in 1938 marked the beginning of the first, so-called "Golden Age" of American superhero comics. The term Silver Age places a character and her stories within a specific period in American culture, "the era when women were portrayed as victims, not having jobs outside of homes, passive, needing to be rescued; women who were sexually independent were not to be trusted. The golden age came out of the pulps and the pulps were by men for men and therefore had little to no interest in women as anything except as an adjunct to men's desires." (Barb Lien-Cooper, "Any Comment?", Silver Bullet Comicbooks Webzine.) This view of women still informs the treatment of female heroes in superhero comics today. While female characters and superheroines have become "strong and assertive", they usually do so only while remaining "sexy" - i.e. existing for the consumption of men - and have in fact become increasingly hyper-sexualized and impossibly musculatured - yet conventionally skinny - since the 1990's.
The "Post Silver Age" or "Bronze Age" in DC Comics was from 1972-1986, and ended with the history-changing "Crisis on Infinite Earths" comicbook event (1985) in which the Silver Age Supergirl and many other main characters died. The Modern Age (1986-present) marks a distinct break with the ages that preceeded it, as DC Comics officially relaunched their comicbook line and began revamping and reintroducing old characters into the "new" continuity.
2. According to canon, Kara's full name is "Kara Zor-El". That is how she refers to herself, and DC continues to use this patriarchal naming convention for the relaunched Supergirl. I can't stand it myself, for obvious reasons. Some modern readers have taken to calling her Kara-El, which is still a patrilineal naming convention, but slightly less odious and peculiar sounding than having her father's full name as her family name.
3. Diana Shutz, The Supergirl Archives, Volume 1, 2001.