Phantom Lady first appeared in Police Comics #01 (Aug, 1941) published by Quality Publications.
The character appeared a further 23 times in Police Comics and in 11 issues of her own named magazine Phantom Lady. Numbering for this publication started at issue #13 - numbering continuing from Wotalife which finished at issue #12.
She also appeared briefly in Feature Comics (issues 69-71) as part of a crossover with 'Spider Widow' and 'The Raven'.
Her last appearance in the Golden Age was in Phantom Lady #23 (April 1949)
Her alter ego was Sandra Knight, the beautiful daughter of U.S. Senator Henry Knight. This first issue established that it was not her first appearance as the Phantom Lady, but it did not go into her origin. When the character was resurrected decades later by DC Comics she was given a proper origin, which was altered several times to give Sandra a more active role.
Sandra Knight assumed the identity of Phantom Lady, 'Mistress Of The Dark', in a costume consisting of a green cape and the equivalent of a one-piece yellow swimsuit. She used a 'black light projector', a device which allowed her to blind her enemies and make herself invisible. She drove a car whose headlights also projected black light when necessary. She was sometimes assisted by her fiance, Donald Borden, an agent of the U.S. State Department.