This is an adventure book. The development of radio telephony is still in its infancy at this time of writing in 1922. And yet it has made strides that were undreamed of in 1918. Experiments made in that year in Germany, and by the Italian Government in the Adriatic, enabled the human voice to be projected by radio some hundreds of miles. Today the broadcasting stations, from which nightly concerts are sent far and wide across the land, have tremendous range. Estimates compiled by the various American companies making and selling radiophone equipment showed that in March of 1922 there were more than 700, 000 receiving sets installed throughout the country and that installations were increasing so rapidly it was impossible to compute the percentage with any degree of accuracy, as the gains even from week to week were great. When you boys read this the problems of control of the air will have been simplified to some extent. Yet at the beginning of 1922 they were simply chaotic. Then the United States Government of necessity took a hand. The result will be, eventually, that certain wave lengths will be set aside for the exclusive use of amateurs, others for commercial purposes, still others for governmental use, and so on. In this connection, you will note that in the story Jack Hampton's father builds sending stations on Long Island and in New Mexico. This is unusual and requires explanation.