The continuing debate over the existence or non-existence of formal verbal aspect in Gothic triggered the author to write this monograph whose aim is to provide a completely new foundation for a theory of aspect and related features. Gothic, with its limited corpus, representing a translation of the Greek, and showing interesting parallels with Slavic verbal constructions, serves and an illustrative model for the theory. In Part I the author argues that a unified theory of aspect, actional types, and verbal velocity presented there possesses an internal logic and is not at variance with observed facts in various Indo-European languages. In Part II an analysis is presented of the Gothic verb system which seeks to explain the much-disputed function of ga- and to solve the problem of Gothic aspect and actional types which does no violence either to the Gothic text or the Greek original.