Also, when people say print on demand, that's not what they mean. It's more akin to ordering a pizza*, and means the printer folks don't actually print any books until you place an order from their website. Then they print out one copy just for you, and ship your hot and fresh sourcebook directly.
*I really hope your local pizza places wait until you actually order before making the pizza. Unlike books, pizzas don't last very long after they've been printed and bound.