Mastriano's first book, "Alvin York: A New Biography of the Hero of the Argonne" (), was published by the University Press of Kentucky in 2014. He conducted twelve years of research for the book. In all, Mastriano reportedly spent 2,000 hours doing research on Sergeant Alvin York, including 1,000 hours studying archives in the United States and various parts of Germany including Stuttgart, Freiburg, Potsdam, Rottweil, and Ulm, and another 1,000 hours of field research in the Argonne Forest of France to locate where York fought during the Meuse–Argonne offensive of World War I. His team uncovered thousands of artifacts related to York's battle of October 8, 1918. Along with research, the book incorporates forensic study and military terrain analysis. Other researchers have questioned the accuracy of the book, including one who has identified 35 citations in the work that he asserts are fraudulent (i.e., not supporting the claims they are cited to support or having obviously doubtful reliability), and a photo on the dust jacket that is labeled by the Army as having been taken twelve days before York's Medal of Honor action but is presented as depicting the action's aftermath. The University Press of Kentucky, which published the book, and the University of New Brunswick, which granted Mastriano his Ph.D. degree for the research, have been reported to be investigating the accusation.