Thomas Allen, Toronto, 1957.  Hard cover, 159 pages.  Very good; red boards with red lettering on black block on front, black lettering on spine.  Binding sound with a very slight lean; some age spotting on outer page block.  Dust jacket has a bit of edge and cover wear, short tears at upper spine edges; some age toning.  Interior clean and unmarked with lightly tanned pages; some off-setting on end papers from jacket flaps.  ‘A revolutionary spark, touched off in a far away country and the subsequent entry into Canada of a fraudulent foreigner who plans to upset U.S.-Canadian military strategy, brings the role of the triple radar “fence” into sharper focus.  Dale, trailing espionage specialists from Europe, pursues criminals masquerading as Oblate Missionaries, unravels some of the fascinating developments that went into the building of the radar networks, follows with dogsled and aeroplane chases across the top of the world, to round up a vast ring of intelligent agents.’ (from front flap)