Le Queux was a journalist, fancier of airships of all sorts, and an early radio pioneer. He wrote hundreds of spy and adventure stories as well, many of them laced with elements of what might be considered science fiction intermingled with historic facts and locations. The "triangle" in this book is a team of three adventurers, Dick, Jules, and Yvette, who begin as spies and soon become involved in solving non-military mysteries as well. No copyright date is given, but the collection of short stories looks as if they were originally published serially, perhaps in a magazine, and later gathered into book form. the technology and events of the stories would date them sometime in the previous decade. Dick is the inventor, who comes up with amazing machines that always are available just in time to solve a problem. Yvette is the daring operative willing to invade any space at all risks, while Jules is the "muscle" who stands guard, ready to rescue Yvette at any time. Heavier than air flying machines, radio, and miniature electronics were all new concepts at the time, and all find their way into the stories. The final adventure deals with the theft and recovery of a valuable supply of radium, and the penultimate story is an echo of Arthur Conan Doyle's The Hound of the Baskervilles.