This is the translation of the first volume of the Russian edition of Vygotsky's Collected Works. It contains several of Vygotsky's major theoretical papers, a number of discussions of the work of outstanding contemporaries, and his manuscript on the crisis in psychology. Together these allow us to get a fairly adequate impression of Vygotsky the theoretical psychologist (as opposed to Vygotsky the educationalist, clinician, experimenter, etc.). Before we turn to a short overview of these texts, it is important to make a few remarks about the selection of texts for this volume (and for all six volumes in general) and their status. We believe that it is fitting to make these remarks in a volume that in the Russian edition formed the first of the whole series.