According to an entry in my book of engagements, I left London for Ravensdene Court on March 8th, 1912. Until about a fortnight earlier I had never heard of the place, but there was nothing remarkable in my ignorance of it, seeing that it stands on a remote part of the Northumbrian coast, and at least three hundred miles from my usual haunts. But then, towards the end of February, I received the following letter which I may as well print in full: it serves as a fitting and an explanatory introduction to a series of adventures, so extraordinary, mysterious, and fraught with danger, that I am still wondering how I, until then a man of peaceful and even dull life, ever came safely through them.