The Diary of Second Lieutenant John L. Hardenbergh, Second New York Continental Regiment, May 1st to October 3rd, 1779, in General Sullivan's Campaign Against the Western Indians, with an Introduction, Extensive Historical Notes, and Battle Maps, is written by Hardenbergh himself, who served in the Revolutionary War . In this book, Second Lieutenant Hardenberg describes in detail the three months of campaign that he spent, which are of great importance in American history. The author shares his impressions, inhibitions and joys, reflecting the tragic and heroic moments of a soldier's life in that difficult time for the country. In addition, the book contains important historical appendices that expand the reader's understanding of that era. These appendices include detailed commentaries, explanations, and cartographic materials that help to visualize the strategic and geographical context of the events described by Hardenberg. "The Diary of Second Lieutenant John L. Hardenberg" is a valuable document that helps us better understand the history of the struggle for freedom and the destiny of the nation, as well as reveal the heroism and courage of those who gave their lives for independence.