This woful History began in my study of the Pelham Papers in the Additional Manuscripts of the British Museum. These include the letters of Pickle the Spy and of JAMES MOHR MACGREGOR. Transcripts of them were sent by me to Mr. ROBERT LOUIS STEVENSON, for use in a novel, which he did not live to finish. The character of Pickle, indeed, like that of the Master of Ballantrae, is alluring to writers of historical romance. Resisting the temptation to use Pickle as the villain of fiction, I have tried to tell his story with fidelity. The secret, so long kept, of Prince Charles’s incognito, is divulged no less by his own correspondence in the Stuart MSS. than by the letters of Pickle.