A brief reconstruction of the first two sections of Edmund Husserl's Vorlensungen zur Phänomenologie des inneren Zeitbewusstseins is done, showing how, making use of the phenomenological method, the author develops his transcendental theory of time. A revaluation of the meaning of "perception of time" allows him to establish the basis which are, in our perspective, able to give an account of one of the most debatable questions about time, its asymmetry or unidirectionality. We furthermore discuss the main difficulties that affect Husserl in this project.