Note: This is the page for the original Batwoman, for the current Batwoman, see Kate Kane
Kathy Kane was created by Bob Kane and Sheldon Moldoff.
The original, Pre-Crisis on Infinite Earths Batwoman first appeared in Detective Comics #233. Batwoman's final appearance is in Detective Comics #485.
Katherine "Kathy" Kane spent her youth as a circus acrobat and daredevil. She was also the heiress of a wealthy family and inherited a fortune as a young woman. Enamored with Batman, Kathy Kane decided to dress up as Batwoman to entice the Batman and combat crime like he did. Batman was concerned for Batwoman's safety and often tried to discourage her so she could give up the cowl and cape. Kathy Kane retired for a short time as Batwoman, diving into her role as a Gotham City socialite, but she missed the thrill of being Batwoman. She got in costume once again to save Batman, Robin, and Superman during a mission, but continued to be dissuaded from staying as Batwoman due to the risk of being a crime-fighter. However, Kathy grew defiant and proved her skills as a crime fighter and a detective, impressing Batman. Kathy's niece, Betty Kane, came to visit in Gotham City and discovered her aunt's secret life. She immediately wanted to become a masked crusader as well and created the persona Bat-Girl. Kathy had to relent and allow her to join because Betty threatened telling others her secret identity. It was around this time that Kathy showed her romantic feelings for Batman, as Bat-Girl showed them for Robin.
On a particular mission against Catman, Kathy Kane infiltrated Catman's gang and became the Cat-Woman, his partner. However, this was a ruse to simply tell Batman and Robin where Catman's headquarters were.Kathy Kane eventually retired her secret identity and purchased a carnival, in Providencetown. She sporadically donned the Batwoman identity to help out the newest Batgirl, Barbara Gordon, on some adventures, but not too often. The League Of Assassins targeted Kathy Kane for a job under the order of their leader, Ra's al Ghul. His true intention was simply to manipulate Batman. Batman appeared in Providencetown to assist Kathy, but it was too late. He was knocked out and she was killed by the assassin known as the Bronze Tiger.
Following the Infinite Crisis, Kathy has been reinstated to her status as Batwoman, separate from Kate Kane. She was an older, rich woman who, out of boredom, decided to become the Batwoman. Her death at the hands of Bronze Tiger is presumably still canon.
During Grant Morrison's run on Batman Incorporated it is revealed that Kathy's real name is Kathy Web, marrying into the Kane's through a late but beloved husband Nathan Kane. Before his death he gave to her Kane's Kolossal Karnival, a gift she had always wanted. It was here at the Karnival that Kathy met Agent-33 of Spyral, who had come to give her a membership as well as an assignment. This assignment would then put her into her 'Batwoman' persona, the head of Spyral, Agent-Zero, wanting her to find out more information involving Batman. Kathy would soon fall in love with Batman, while at some point having an affair with Agent-33. After Batman proposes to her, she learns that Agent-Zero, while also being a nazi super-criminal, is her father, and because of this she is forced to break up with Bruce. It was also stated that before working for Spyral she was also a member of another intelligence agency, a film director, and a published poet.
However, while Batman and the rest of the world believing her to be dead, there is a strong possibility of her being alive and well and also having ties to Leviathan. Proof to this being a woman with black hair and similar figure talking about Batman and how "He hated flowers". Whether or not Kathy really is alive is yet to be known.