Found this vintage paperback at a local antique shop. According according to Wikipedia, the author John Lee based this tale upon a real Nazi spy plot called Operation Pastorius. I had no prior knowledge of this plot. I also didn't know Collier published a Spymasters series in the 1970s. The consulting editor for the series was Saul A. Katz founder of the 999 Bookshop in New York City. I included a photo of the page that listed some of the other titles in the series.
From his NYT published obit:
"Saul was known to East Siders as the enthusiastic and knowledgeable owner of the 999 Bookshop on Madison Avenue. He championed liberal political writers and had a special fondness for well-written spy novels. He never gave up on the Mets. "
I thank both Saul and Collier and look forward to finding other books from this series.
