This book bears mention in Gaiman books from time to time, and if you look hard enough, some Pratchett, too. Generally it is for summoning Death or a Horror from Beyond. I was just thumbing through Sandman a bit back and it caught my eye. Something was not right with this! I had never seen it mentioned anywhere else! Bust out that thinker, hero!
So after a bit of contemplation, I am now sure that the book's title is dog Latin for "the book of yellow pages". The shade of yellow it mentions is a little different from the one the phone companies use, but. It's Pratchett's Necrotelecomnicon.