'THE secret invention of an almost invisible aeroplane is the cause of this exciting spy yarn, and a particularly suave and particularly ruthless agent of an unspecified European country keeps it moving. An old friend, Gilbert Larose, in the role of a secret service agent, however, proves equally as ruthless and even more cunning, so the honors are satisfying. Murder and kidnapping help the foreign agent to secure the prized formula for making the material for the plane, but his seemingly faultless disguises and alibis are easily penetrated by Larose. There are many moments of anxiety, but a villain must never succeed in his dastardly plots — in fiction.'
'Bodleian'. 'Leaves from the Latest Books', The Mail, 21 August 1937, p.27.