Leonard Norman Wein was an American comic book writer and editor best known for co-creating DC Comics' Swamp Thing and Marvel Comics' Wolverine, and for helping revive the Marvel superhero team the X-Men. Additionally, he was the editor for writer Alan Moore and illustrator Dave Gibbons' influential DC miniseries Watchmen.

The Swamp Thing is a superhero in American comic books published by DC Comics. A humanoid/plant elemental creature, created by writer Len Wein and artist Bernie Wrightson, the Swamp Thing has had several humanoid or monster incarnations in various different storylines. The character first appeared in House of Secrets #92 in a stand-alone horror story set in the early 20th century. The character then returned in a solo series, set in the contemporary world and in the general DC continuity. The character is a swamp monster that resembles an anthropomorphic mound of vegetable matter, and fights to protect his swamp home, the environment in general, and humanity from various supernatural or terrorist threats, his archnemesis being the sorcerer Anton Arcane.