Alan Moore was a prolific and very influential comic book writer
during the 1980s. He is British
and hails from the town of Northampton
(where I believe he still lives).
He started out writing in the UK for 2000AD. He created a number of memorable series for this publication D.R. & Quinch, Skizz, and Halo Jones being the best known. He also wrote a large number of short twist in the tail stories called Future Shocks.
He also took over the writing of the UK only version of Captain Britain and working with the artist Alan Davis they created a parallel reality spanning epic (a topic Moore has returned to since).
After he created several series in an independantly produced British comic called "Warrior". These included "V for Vendetta", "Marvelman" (later renamed Miracleman to avoid trademark issues) and "The Bojeffries Saga".
He really came to the attention of the American public when he went to work for DC Comics and took over the Swamp Thing comic book. He turned the entire concept of the book on its head starting with his second issue "The Anatomy Lesson". He made it the top selling horror title for DC at the time. When the Comics Code Authority actually read an issue they refused to sanction it and DC simply published it and all future issues without the stamp.
He then created the classic limited series Watchmen with Dave Gibbons. In this they examined the entire idea of how society might respond to the existence of superheroes. This is still considered by many to be one of the best comics of all time (myself included).
During this period he also wrote the classic "Killing Joke" which examined the psychology of the Batman and the Joker. This was illustrated by Brian Bolland.
He then tried to branch out and create a series called "Big Numbers" (originally "Mandelbrot Set") that was to follow the development of a shopping mall in a small town (if I remember correctly). This however suffered from terrible delays and poor sales and folded after I think 3 issues.
At this point I will have to admit to not knowing really what he did for some time.
However Alan Moore is now driving the production of America's Best Comics (indirectly from DC via Wildstorm). He is basically writing all their comics including "Tom Strong", "Top 10", "Promethea", and "Tomorrow Stories" (an anthology title). There was also a limited series called "The League of Extraordinary Gentlemen" which starred characters from fiction at the end of the 19th century such as Captain Nemo, Mr Hyde, and Allan Quartermain.
Alan Moore was also a bit of an artist creating a somewhat surreal comic strip for his local called "Maxwell the Magic Cat". He did it originally under the name Jill de Ray.
He also drew a strip for a UK music paper (I think it was Sounds) called "The Stars my Degredation". This was where the psychotic axe wielding assassin Axel Pressbutton first appeared. He did this under the name Curt Vile.
Alan Moore had a reputation for enormous scripts
that were excruciatingly detailed (the graffiti
on a bench in the background of a panel is a common example). I think it was Dave Gibbons once joked that he used to tear every second page out of an Alan Moore script in order to be able to draw it.
Neil Gaiman's first exposure to a comic script was I believe one of Alan Moore's and he too now writes similarly detailed scripts.