"From Hell", for those who do not know, is a graphic novel written by Alan Moore and illustrated by Eddie Campbell which tells a story based on the infamous Jack The Ripper murders. "From Hell" is a massive work with an extensive appendix and contains countless details about the city of London. It is actually possible to take yourself on a tour of some of London's more mystical sites with this book as your guide. I know. I've done it.
I'm not sure if it adds to the book's legitimacy or takes away from it, but "From Hell" will reach a mass-market audience in 2001 when the movie version (starring Johnny Depp) is released.