Historiography is the study of how history is written and how our historical understanding changes over time. Historiography looks at the approaches used by historians and considers why their theories and interpretations are often different. While the past itself never changes, history – which tries to form an understanding of the past – is always shifting and evolving. New historians approach the past with their own methods, priorities and values. They develop new theories and conclusions that change the way we see and understand the past. Historiography acknowledges and discusses this process of change. Historiography is a difficult and complex field of study. It is a critical component of most college or university level history courses, where students are expected to know about the past and how it has been interpreted over time. Many senior secondary and high school courses also include some basic historiography, usually through the study of different historians and competing historical perspectives. Historiography changes over the time based on the event happening in our world.