The Iron Codex by David Mack
1954: In Southeast Asia, Cade Martin, hero of the Midnight Front during World War II, chases ghosts and flees his past. In the United States, Briet Segfrunsdottir heads the Pentagon's top-secret magickal warfare program. And In South America, Anja Kernova hunts fugitive Nazi sorcerers with the help of a powerful magickal tome known as the Iron Codex. In an ever-more dangerous world, a chance encounter sparks an international race to find Anja and steal the Iron Codex. Anja is hunted by friend and foe alike as they approach a showdown on Bikini Atoll in March 1954: the Castle Bravo nuclear test, where science and black magic are destined to collide.