A mysterious black-mail ring operates in England -- a ring whose demands can be ignored only at the risk of deadly peril, and whose calling card is an iconic red circle. Scotland Yard's finest seem unable to stop the ring's predations and even the noted private detective Derrick Yale seems always to be one step behind. But who, or what, is the Crimson Circle? Is it a clever group, a single man, or . . . even a woman? This is the riddle that must be answered to stop . . . The Crimson Circle