The Diary of a German U-boat Commander, With an Introduction and Explanatory Notes by Etienne, by Stephen King-Gall, Knight, is an interesting piece of literature that tells the story of the life and work of a U-boat commander during the First World War. In this book, the reader will immerse himself in the atmosphere of the submarine military fleet and experience all the trials that awaited sailors in the dangerous waters of military confrontations. With the introduction and explanatory notes by Etienne, the reader will be able to better understand the context and events described in the commander's diary. This book will be of interest to those interested in military history, naval adventures, and in-depth analysis of warfare.