To the best of my knowledge, Crooked Little Vein is the first novel by prolific comic book writer Warren Ellis. Let me see if I can sum up the plot.
A heroin addicted US chief of staff hires a Manhattan private investigator, Mike McGill, to find an alternate US constitution. The book was written by the founding fathers of America and details their true plans for the country. Richard Nixon lost the book in the 50's and since them American society has been getting progressively worse. The trail leads Mike on a cross country chase for the book where he encounters every sort of depravity you shouldn't be able to imagine.
I was constantly laughing out loud during while reading this book. The deviants and underground cults that Mike finds himself getting involved with are disturbingly funny. The message that is coming across is that the underground is now mainstream. Anything you can think of can now be found on-line. It's like the ultimate long tail example.
If you are unable to keep an open mind this book is probably not for you but if you can get passed the descriptions of sexual situations you will really enjoy this noirish detective novel.