First English Edition, Advance Review Copy in original illustrated wrappers. E. Welch Ridout cover art. Extremely rare Hubin listed mystery title to be found in original advance state wrappers, with remnants of 7/6 price sticker at spine, a price reserved for hardcover editions published by Stanley Paul. Interesting copyright statement "Copyright in the United States of America by The Macaulay Company, New York, 1922." The first American Edition is believed to be published by Moffat, Yard and Co. and not Macaulay who apparently owned the rights. The jacket press from that Moffat edition states the following about his title: "Here is the first book of fiction that embraces one of sciences greatest achievements. Falconer is called upon by Scotland Yard to aid in the detection of a group of criminals who have turned the uses of radio into lawless channels. Acknowledged as the greatest radio expert of his day, Falconer traps them in his own radio net and brings them to belated justice... Truly the guilty secrets of many men and women have been detected by means of wireless, that science which daily reveals its further wonders to those persevering experimenters who seek so patiently to penetrate its mysteries." Very Good plus, some modest shelf wear, minor loss at spine ends, few pages lightly bumped at fore-edge.