German Spies in England by William Le Queux

There is a vast amount of misconception in the public mind on the subject of spying, and an almost complete ignorance of the law of dealing with spies, military and civil, in time of peace and in time of war.

The subject is one which absolutely bristles with anomalies and incongruities. In all times and in all countries, and by the great majority of people, spying has been condemned as something essentially dishonourable -- to call a man a spy has always been regarded as one of the deadliest insults. Yet here we have at once the first, and perhaps the most striking, anomaly of the spy business -- the men of unblemished personal honour, who, unquestionably, would not descend to any act which, in their views, was even tainted with meanness, have acted as spies. I will mention a few of these cases presently; in the meantime, it will be well to consider what international law has to say on the subject.