This book is based on personal recollections of participants in the events described in it and official documents of the US Marine Corps, stored at the Marine Corps History Center in Washington. The historical basis of the book "Marine Corps Sniper" was combat orders, directives and orders, operational reports and mission reports. In describing enemy actions, those events that did not come to the attention of the Americans were reconstructed on the basis of evidence discovered after the fighting. In some cases, I was incredibly lucky: after her death, the Apache notebook, in which she daily wrote down information about her movements and the results of her observations, as well as information about skirmishes with the Americans, fell into the hands of a Marine from Hill 55, who lent it to me her for work on the book. In several places I took the liberty of inventing words spoken by Hathcock's opponents from the North Vietnamese Army and the Viet Cong. These are the only places in the book that cannot be fully confirmed as a result of a careful study of the available documentary materials. I tried to present everything else as best I could in accordance with the real facts.