
Dennis Joseph O'Neil (May 3, 1939 – June 11, 2020) was an American comic book writer and editor, principally for Marvel Comics and DC Comics from the 1960s through the 1990s, and Group Editor for the Batman family of titles until his retirement.
His best-known works include Green Lantern/Green Arrow and Batman with Neal Adams. It was during this run that O'Neil co-created the Batman villains Ra's al Ghul and Talia al Ghul. His other notable work includes runs on The Shadow with Michael Kaluta and The Question with Denys Cowan. As an editor, he is principally known for editing the various Batman titles. He also sat on the board of directors of the charity The Hero Initiative and served on its Disbursement Committee.
Description above from the Wikipedia article Dennis O'Neil, licensed under CC-BY-SA, full list of contributors on Wikipedia.

Knight Immortal
2019 · as Self

Masterpiece: Frank Miller's The Dark Knight Returns
2013 · as Himself

Joker: Put on a Happy Face
2020 · as Self

Comic Book Superheroes Unmasked
2003 · as Self

Secret Origin: The Story of DC Comics
2010 · as Self

The Fire Rises: The Creation and Impact of The Dark Knight Trilogy
2013 · as Self

Look, Up in the Sky! The Amazing Story of Superman
2006 · as Self

Batman Unmasked: The Psychology of The Dark Knight
2008 · as Self

Legends of the Dark Knight: The History of Batman
2005 · as Self

Comic Books & Superheroes
2001 · as Self

Robin: The Story of Dick Grayson
2010 · as Self

The Science of Superman
2006 · as Self

The Legends Behind the Comic Books
2007 · as Self

Superman vs. Batman: When Heroes Collide
2013 · as Self

Robin's Requiem
2010 · as himself

Heart of Vengeance: Returning Batman to His Roots
2011

Batman Year One: A Conversation with DC Comics
2011