The use of critical exposition of previous doctrines is a methodological procedure usual in Aristotle. But the distinctive characteristic of Book I of the Metaphysics is that, rather than to establish a new doctrine, a review of predecessors serves to confirm the own concepts to be used in the evaluation of the doctrines examined. This imposition of own terms has cost him the charge of distorting historical understanding. With the detailed analysis of the criticisms of Plato's theory of Ideas in (...) Metaphysics I, 9, we intend to show a) that the criticism of manipulation and distortion of his predecessors' views overshadow the degree to which Aristotle's own positions emerge from a critical review of previous thought and b) that the imposition of own terms does not suppose a distortion but a proposal of solution to the problems that previous theories have left unresolved. (shrink)