The Divine Yellow Pages is a book of contact information for various deities of the NeSiverse, including the Terran Deities of Earth. This allows gods to find other gods.
Highemperor and Soriel's Adventures in SPAAAAAACE!!!
Runekeeper once attempted to use the Divine Yellow Pages to seek out the contact information for Earth's god of magic, only to find no such listing in the book[Pan 1]. What he didn't realise is that there is no one single god of magic on Earth but a plethora of them (citation needed).