Each person is perceived by others and by herself as an individual in a very strong sense, namely as a unique individual. Moreover, this supposed uniqueness is commonly thought of as linked with another character that we tend to attribute\nto persons (as opposed to stones or chairs and even non-human animals): a kind of depth, hidden to sensory perception, yet in some measure accessible to other means of knowledge. I propose a theory of strong or essential individuality. This theory is (...) introduced by way of a critical discussion of Van Inwagen’s and Baker’s ontologies of persons. Composition\nTheory and Constitution Theory are shown to be complementary, in their opposite strong and weak points. I argue that both\ntheories have unsatisfactory consequences concerning personal identity, a problem which the proposed theory seems to solve\nmore faithfully both to folk intuitions and the phenomenology of personal life. (shrink)