Fall from Valhalla — Mike Whicker

In the months just after the end of WW II, two deadly and cunning women find themselves pitted against each other in a lethal game of cat-and-mouse. One was Nazi Germany's top spy now working for the United States: her opponent, Soviet Russia's most feared assassin. Fall from Valhalla is a superbly researched uber-thriller set in the clandestine world of undercover 'spooks' and 'ghosts' operating during the earliest days of the Cold War.