Einstein"s Revolution is a textbook on relativity written from a historical-methodological point of view. It can be used as an account of Einstein"s physical theory even if the reader has no sympathy with the author"s philosophical standpoint, or it can be read for the author"s philosophical argument, without the reader having to follow all the details of the physics. The work challenges a distinction made by the Vienna Circle an still influential today: the distinction between "the context of discovery" and "the context of justification." According to the traditional view, the context of discovery calls for no rational reconstruction and belongs, in effect, to psychology, while only latter is subject to a proper logic of appraisal. Against these theses, Zahar shows that there is a logic of discovery and that it plays an important role in the appraisal of theories.