Here is George S. Patton Jr.'s official war diary with daily entries from September 1918 to the days leading up to the Armistice in November. He kept it while commanding the 304th Tank Brigade in World War I. Also included is the war diary of Ranulf Compton, one of his battalion tank commanders, with daily entries from mid-August to mid-October. Both diaries cover in detail tank operations at the Battle of St. Mihiel and the Meuse-Argonne Offensive, providing a candid look at the successes and challenges of early tank units in combat. Compton's diary entries are particularly intriguing because he is a lesser-known figure historically but one who played a critical role in the final days of the war. Sereno Brett, Patton's other battalion commander, had assumed command of the brigade after Patton was wounded the last week in September. Compton, in turn, assumed command of all the brigade tanks at the front. His role as commander of the fighting tanks makes his diary entries especially important. Once Patton was medically evacuated off the battlefield, his knowledge of tank operations was strictly second-hand. But Compton was now eyewitness to several more weeks of some of the toughest fighting of the war. The contrast between Patton's and Compton's diary entries is also intriguing for another reason. On a personal level, Patton had a vested interest in the success of the early tank, having been an early proponent and personally involved in its development. But Compton had no such investment and therefore his daily observations, in contrast to Patton's, contain a more unvarnished assessment of the early tank.