The Magician's Companion

From the back of the book:

This sourcebook covers the magic of the Secret World, including an open-ended creative system that allows magicians to do whatever they possess the will, energy, and desire to achieve. Traditional magical paths featured include Druidism, Voodoo, Witchcraft, Shamanism, Chaos magic, Enochian magic, Hermetica, and more..In addition, a complete chapter details the Osirians - the thirteent race of inmortals - including their magic, history, mythos, culture, nature of inmortality, and so on. Complete spell and rituals are provided, along with numerous magical places. Also featured are many Secret Societies and an earth-like world openly ruled by mages and organizations that exist there.