This was the first "big" Saint novel—that is, the first story in which he went up against king-size international dragons, as against the ordinary leeches, rats, skunks, and other vermin of the Underworld—and it still seems to be one of the prime favorites of those loyal readers who have followed his adventures almost from the beginning.
For the benefit of those who may be taking up the series so much later, however, I feel it may be necessary to slip in this reminder that the book was written in 1929, when the world was politically, technologically, and temperamentally a totally different place from the one we live in today.
In those days, there was a genuine widespread suspicion, which I was inclined to share with a great many of my generation, that modern wars were plotted and deliberately engineered by vast mysterious financial cartels for their own enrichment. There was also a vague idea that fighting, itself, was still a fairly glamorous activity, or would be if the scientists would leave it alone. No doubt there were romantics in other periods who thought it was more sporting to be shot at with arrows than with bullets, and they were followed by others who thought that rifles were more fun than machine-guns and howitzers, and after them came those who thought that poison gas the last step to reducing glorious war to sordidness.
This book is based on the Saint's accidental discovery that the usual slightly goofy scientist has dreamed up something called an "electron cloud", a sort of extension of the gas horror with radioactive overtones, and his decision that it should not only be kept out of the hands of the stateless war-mongers, but for the good of humanity should be suppressed altogether, on the theory that this would still leave heroes happily free to enjoy the relatively good clean fun of air raids and ordinary mustard gas. (The original title of the book was The Last Hero, and in it the Saint first expounded his philosophy of "battle, murder, and sudden death" as a joyous form of self-expression.)
Well, this was an attitude of youth which of course I shared with him, or he got from me. And in those days there were no mushroom clouds on the horizon to make even Vargan's electron cloud look like a comparatively harmless toy. But this should not for a moment be taken to imply that either of us, today, would be supporters of the "Ban the Bomb" kind foggy-minded idealism. There are many things which seemed like eternal truths to both of us in those days, which no longer look so immutable. In fact, I myself am often tempted now to lean with the optimists who think that the Bomb may actually achieve what the moralists failed to do, and abolish major warfare by making it impossible for anyone, financier or despot, to hope to profit by it.
Be tolerant, then, of one or two outworn ideas, and enjoy it simply as a rattling good adventure story of its time, which I think it still is.