This document discusses historical research methods. It defines historical research as the systematic collection and critical evaluation of past data to answer questions about causes and effects of past events. The key steps are: 1) collecting primary and secondary sources; 2) critically examining sources through external and internal criticism; 3) objectively presenting the facts without bias. Historical research allows investigation of topics not studyable otherwise, but limitations include lack of control over threats to validity and representation of samples. Areas of study include periods, locations, and military history.