How many issues of Swamp Thing did Alan Moore write?

Alan Moore wrote a total of 68 issues of "Swamp Thing," covering issues #20 to #64, as well as the annual #2. His groundbreaking work on the series is credited with redefining the character and elevating the comic book medium through its exploration of Horror, philosophy, and environmental themes. Moore's run is widely regarded as one of the best in comic book history.