Historical research involves systematically collecting and analyzing past data and evidence to understand and explain events or actions. It has several purposes, including helping people learn from the past, understanding present practices, and testing hypotheses. The key steps are defining the research problem, locating primary and secondary sources, summarizing and evaluating the sources, and presenting interpretations of the information. Historical research allows investigating topics not possible through other methods but also has disadvantages like an inability to control for threats to validity from studying only past events.