Harley Quinn

Harleen Frances Quinzel began her career as a promising psychiatrist assigned to Arkham Asylum, where her obsessive fascination with one particular patient — the Joker — unraveled everything she had worked for. That patient twisted her devotion into something dangerous, and Harley Quinn was born. Armed with a giant mallet, acrobatic agility, and a chaotic energy all her own, she exploded onto the scene as one of the most instantly recognizable figures in DC Comics history. Her origin as a credentialed professional who chose madness over normalcy gives her a psychological depth that sets her apart from nearly every other character in the rogues gallery.

For collectors, the key book is The Batman Adventures #12 from 1993 — her comic debut following her breakout appearance in Batman: The Animated Series. That issue is one of the most sought-after modern-age keys in the entire hobby, consistently commanding strong prices in high grade. Her mainstream DC Universe introduction came later, and her first ongoing solo series launched in 2000, but it's that 1993 animated-universe appearance that remains the crown jewel for any serious Harley Quinn collection. She has since become one of DC's most versatile characters, moving fluidly between villain, anti-hero, and unlikely hero depending on the story.

Harley's team history is as stacked as any character in comics. She's been a core member of the Suicide Squad, a founding figure of the Gotham City Sirens alongside Catwoman and Poison Ivy, a recurring presence in the Secret Six, and even a member of the Birds of Prey. Her solo titles have explored everything from street-level Brooklyn vigilantism to cosmic adventures with the Red Lantern Corps, and her Gang of Harleys era introduced a whole new supporting cast that collectors have embraced. She's also appeared prominently in Injustice tie-in comics and various DC event crossovers, making her appearances extensive across multiple eras of publishing.

Few characters in the modern age have ascended from a single-episode animated cameo to full-on franchise status the way Harley Quinn has. Her books are worth collecting not just for the key issue value of The Batman Adventures #12 — though that alone justifies attention — but because her publishing history is rich, varied, and still growing. First appearances of her major supporting characters, her early Suicide Squad appearances alongside the New 52 relaunch, and her ongoing solo titles all offer entry points for collectors at every level. Whether you're hunting slabbed keys or building a complete run, Harley Quinn's corner of DC is one of the most rewarding in the hobby.