Debates between historians show that they expect descriptions of past people and events, and interpretations of historical subjects, and genetic explanations of historical changes, to be fair and not misleading. Sometimes unfair accounts of the past are the result of historians' bias, of their preferring one account over others because it accords with their interests. It is useful to distinguish history which is misleading by accident from that which is the result of personal bias; and to distinguish personal bias from (...) cultural bias and general cultural relativity.This paper explains what fair descriptions, interpretations, and explanations are like in order to clarify the senses in which they can be biased. It then explains why bias is deplorable, and after noting those who regard it as more or less inevitable, considers how personal bias can be avoided. It argues that it is not detachment that is needed, but commitment to standards of rational inquiry.Some might think that rational standards of inquiry will not be enough to avoid bias if the evidence available to the historian is itself biased. In fact historians often allow for bias in evidence, and even explain it when reconstructing what happened in the past.The paper concludes by noting that although personal bias can be largely avoided, cultural bias is not so easy to detect or correct. (shrink)