Put simply, historiography is the study of history as a discipline. This includes the methodological and epistemological issues raised by the study of history over time. Essentially, to study historiography is to put various historical interpretations in their own contexts, including the societal, cultural, and even personal factors that influenced these interpretations. To cite a brief example, in the 1960s, changes in society, as well as new technological developments, contributed to a new interest in social and cultural history, which had been largely ignored by previous generations of historians who had been primarily interested in political and diplomatic history.
Historiography is of major interest to historians, and in fact is fundamental to every field within the discipline. Many prominent historians publish essays and even books that survey the historiography of their field, and it is a major focus of graduate school training for historians, as much, even, as developing research skills. Almost every published article, book, of dissertation intended for scholarly readers begins by surveying the relevant historiography, in this sense, what previous historians have had to say about the topic of the book. In that way, historians show how their argument is original and important.