History is the study of change over time, and it covers all aspects of human society. Political, social, economic, scientific, technological, medical, cultural, intellectual, religious and military developments are all part of history. Usually professional historians specialize in a particular aspect of history, a specific time period, a certain approach to history or a specific geographic region

Non-historians often say that “history repeats itself” or that “things were always this way.” History cannot repeat itself because history is not a living, thinking being.