I've always been a fan of mythology, dating back to my pre-teen years reading about the Greek and Norse gods and not coincidentally right around the time when I started playing D&D. Working as a designer at Wizards I eventually became known as "the gods guy," writing or developing most of the deity write-ups for the World of Greyhawk and the Forgotten Realms. In the last months of Dragon magazine's time at Paizo I wrote a series of Core Beliefs articles for Greyhawk, and when James and Wes wanted to keep the series going with the gods of Golarion they asked if I'd mind continuing it. Of course, I jumped at the chance—how often do you get a chance to shape the mythology of a new published world? Work on those articles naturally led to me filling out the gods section of the Pathfinder Chronicles Campaign Setting, and that led to writing Gods and Magic.
Tackling this sort of project can be daunting. James, Mike, Wes, and Erik all had their ideas about the setting and its history, and all I had were a few paragraphs on each deity, which I had to expand into two-page write-ups that didn't go against their years of home campaigns and office discussions about the world. Fortunately, we had a format that worked—the long deity write-ups in Pathfinder—and the first step was to reduce that format from its 6,000–8,000 word incarnation to a more manageable 1,600–word two-page setup. Stripped down to a leaner form, I knew exactly what topics I had to cover; the challenge was getting into the right mindset for writing about each of the 20 deities, which is where real-world inspiration comes in.
Thousands of years of human history have created hundreds of strange beliefs suitable for adapting into a game. Sacred prostitutes? Check. Mortals making pacts with fiends? Check. Beast-headed protector deities? Check. And so on. Using the references on my bookshelf, bits from the History Channel, and online sources such as Wikipedia, I was able to find idea seeds that I could "game up" for an interesting deity description. The ultimate goal was twofold: one, to make the gods cool enough that GMs think, "I need to get these guys into my game as soon as possible," and two, to make them cool enough that players think, "I want to play a priest of this god as soon as possible.' Depending on the deity, this may require making them sexy (like Calistria), creepy (like Zon-Kuthon), badass (like Iomedae), or some other "hook."
Most of the text in the deity write-ups is "fluff" rather than "crunch"—descriptive material with no game mechanics, useful for getting the feel of a religion but usually not enough to differentiate them when the dice hit the table. Fortunately, this book has a lot of room for crunch; each deity gets a faith-specific spell and magic item, and these help nail down aspects of the god and his or her worshipers as well. For example, there's an Asmodean magic item that lets a worshiper use his own blood to augment certain spells. Calistria's priests can seduce an enemy, then cast a spell to avenge themselves against that enemy. Rovagug's cult has an item that causes rage if the wearer is bound or shackled. Torag's priests have a spell that turns failures into successes. Urgathoa's followers can compel enemies to eat their own fallen comrades. Little things like this help establish the reality in a fantasy world where these gods and goddesses are real.
Gods and Magic was a fun book to write. The work situation was a bit more hectic than my normal experience (near my deadline I had my sister's wedding and moved to Washington to start full-time at Paizo) but I'm familiar enough with the process of writing this sort of material that I could let my instincts steer me true. It doesn't hurt that the rest of the Paizo team is very supportive and gives great feedback—a smart designer quickly learns to rely on these open channels of communication to make their work stronger, and that is precisely what I did. I think this book will become an integral part of your Golarion collection, and I hope you enjoy it.