My only excuse is that it amused me to recall a few of the more interesting cases with which I have been concerned during my professional life, and it seemed that other people might be interested to read my account of these varied investigations.

The book consists mainly of the story of these cases - a plain, unvarnished tale without embellishment or emotion. I trust that my readers will find something of interest in another man's work. Many of the cases have appeared in the professional journals, such as the British Medical Journal and the Police Journal.

These I have freely drawn from. I have to thank many police authorities for their help in letting me have material relating to cases dealt with by me. In particular thanks are due to my old friend Gilbert Watson, who has helped me throughout in the preparation of the text and in the correction of the proofs.
Sydney Smith