The Q-ship, an ordinary merchant vessel with concealed guns, came into its own during World War I, when used by the Royal Navy to trap and destroy German U-boats. The Q-ship operations are covered here in detail, by following the careers of the eight men who won the Victoria Cross on Special Service Operations; and by accounts of German U-boat crews being on the receiving end. No book on Q-ships can avoid the Baralong incident in which a Q-ship's crew allegedly executed the survivors of the German submarine U-27, on August 19, 1915. In a subsequent encounter with U-41, more British atrocities were alleged by the only two German survivors. Revealing extracts from the diary of a Royal Marine who served on board the Baralong are reproduced here, together with other first-hand accounts. With charge and counter-charge, this incident provides a fascinating story.