While a critic measures a speech against a number of standards to determine its worth, a historian attempts to explain it in the context of social-institutional activity. After discussing the differences between rhetorical criticism and rhetorical history, this paper distinguishes among various types of historical explanations, illustrates each type from rhetorical literature, and offers several conclusions that emerge from these distinctions. The paper outlines the following three forms of historical explanations: (1) answering the question, "What is it?" when either no word exists to identify a series of characteristics surrounding an event or potentially more than one word or concept applies; (2) responding to "How did it come to be?" when events are puzzling or unexpected; and (3) applying "Why did it happen?" to relate events and arrive at generalizations or covering laws through induction and deduction. The paper suggests that rhetorical students should continue to examine their logical structures through the rationale and claims of history. (MAI)