Józef Maria Bocheński introduced an important distinction between deontic and epistemic authority. A typical example of epistemic authority is the relation of a teacher to his students; a typical example of deontic authority is the relation between an employer and his employee. The difference between the two lies in domains of authority: declarative sentences make up the domain in the case of epistemic authority, orders—in the domain of deontic authority. In the article, I analyze in detail the concepts of the (...) two kinds of authority and propose some new explications. The concept of epistemic authority is distinguished from the concept of infallibility and expertise; and the concept of deontic authority is distinguished from the concept of sovereign. I interpret various kinds of deontic authority in the light of the theory of imperative sentences. The concepts of gradation and de-gradation of authority are introduced and explicated. (shrink)