Probably few men have travelled so constantly up and down Europe as I have done, in search of material for my books. In the course of my wanderings, and perhaps a somewhat erratic life on the Continent, I have--ever since I recognised the spy-peril--made it my practice to seek out the spies of Germany, and I know a good many of them. An incident which may interest the reader occurred on October 29th, 1914: I was on the platform of Waterloo Station buying a paper, and chatting with the bookstall clerk, when I noticed a group of men, mostly in shabby overcoats and presenting a woebegone appearance, surrounded by a cordon of police in silver-trimmed helmets--county constabulary from the North. An excited crowd had surrounded them, and as I glanced across my attention was attracted by a man slightly better dressed than the others, though his well-cut grey overcoat was somewhat shabby. As his dark, narrow-set eyes met mine, he lifted his grey plush hat to me, and smiled across in recognition. For a moment I halted, puzzled. I had not realised that the group of men were prisoners. The fellow's face was familiar, and the next instant I recognised him. We had met a dozen times in various places in Europe--the last time at Salvini's, in Milan, early in the previous year. He was a well-known agent of the German General Staff, though I had never met him before on British soil. I crossed over to him, arousing the distinct suspicion of the constables and the curiosity of the crowd of onlookers. "You recollect me, Mr. Le Queux--eh?" he asked in good English, with a laugh. "Of course," I said, for I could not help a grain of sympathy with him, for, usually a resident of the best hotels, he was now herded with the scum of his compatriots. "Well, what's the matter?" "Matter!" he echoed. "You see! They've got me at last!" "Speak French," I said in that language. "The police won't understand"; for the constable near him looked at me very suspiciously, and I had no desire to be arrested on Waterloo platform. "_Bien!_" said my friend, whom I will call by his assumed name, von Sybertz, "I am arrested. It is the fortune of war! I am simply detained as an alien, and we are going to Frimley, I hear. Do not say anything; do not make it worse for me. That is all I ask, M'sieur Le Queux. You know me--too well--eh?" and he grinned. "I shall say nothing," was my reply. "But, in return, tell me what you know. Tell me quickly," I urged, for I saw that the constables were preparing to move the prisoners towards the train. "What is the position?" He shrugged his shoulders.