Another in the classic series filled with mystery, murder, and British espionage from the Edgar Award-winning author.   Some parts of the secret service are more secret than others, and Department Z is among them. Now, its founder, Gordon Craigie; top agent Loftus; and their compatriots must face a mysterious international organization that has suddenly gained power and infiltrated the governments of several key global powers. It already has branches operating in at least seven countries and is believed to be responsible for past catastrophic events, including an assassination and a civil war--and is planting the seeds of anarchy once again.   Working together with some foreign allies, they intend to unearth the mystery of "The Ring"--but their cooperation may not be enough to prevent calamity . . .