This volume surveys the historical development of the notion of personality as brought into relief by salient patristic and medieval theologians, culminating with the thought of St. Albert the Great. The philosophical problems of "subsistence", "individuation", "relative distinction" and "signification", amongst others, are ciritically analyzed in an effort to identify the formal constituent of personality (and to resolve the equivocal distinction between "person" and "nature"). Following a detailed exposition of the Albertinian corpus, a final synthesis also examines the personality theories of the Thomistic commentators as well as certain popular modern perspectives, evaluating them in light of the established metaphysical criteria.