The wizard from Northampton. Originally a writer/artist, he realized he couldn't produce artwork fast enough so he took writing only. In his early days he published under the pseudonyms "Curt Vile" (a play of Kurt Weill, an influential German composer from the early 1900's) and "Jill de Ray" (from Gilles de Rais, an infamous French child murderer.)
He broke into comics with the help of his friend and then mentor Steve Moore (no relation.) Later he would help Neil Gaiman break into comics.
He is regarded as one of the comic authors responsible for making comics, dare I say, a "proper" high-brow artform, next to the likes of Will Eisner and Art Spiegelman. On the flipside, he's also partially responsible for the Dark Age of comics, which culminated in the EXTREEEMEEEEEE grimdark era that was most of the 1990s. According to Moore, he wrote works like Watchmen expecting people to realize the potential of comics, but found them focusing on the dark, violent and pessimistic contents instead.
He is currently semiretired from the comics industry. His only upcoming comic book work is the third volume of League of Extraordinary Gentlemen. Most of his time nowadays is spent writing his second novel, protesting against the government shutting down libraries in his hometown, and simply enjoying his time with friends and family.
He has gained a bit of a backlash-driven reputation in /co/ due to his recent statements about the comics industry and, thanks to a silly quote from Grant Morrison, his alleged obsession with rape, which is featured in most of his output (still, he showcases murder on an even more frequent basis but of course nobody accuses him of being obsessed with murder.) But don't let that discourage you: he is a pretty good writer anyways.
Speaking of Morrison, there is an ongoing war between fans of Moore and fans of Morrison (namely those who don't realize they're both great yet flawed authors and believe there can only be one). Expect a thread in /co/ about either of them to turn into a war about who is the better writer or even the better wizard.