It's not a real book. It was part of the Lovecraft/Cthulhu mythos.
Along with The King in Yellow, The Necronimicon, The Book of Eibon (or
Livre d’Eibon),
Cultes des Goules, The People of the Monolith,
The Pnakotic Manuscripts, Seven Cryptical Books of Hsan,
Unaussprechlichen Kulten (a.k.a Black Book, or Nameless Cults), etc.
Here's a link with more info.
Tomes
EDIT: My mistake,The King in Yellow was written by Robert W. Chambers, a long time friend of H.P. Lovecrafts'(1865-1933)
[Edited on 5-2-2004 by darklanser]