More often than not, theories of belief and of belief ascription restrict themselves to conscious beliefs, thus obliterating a vast part of our mental life and offering extremely incomplete, unrealistic theories. Indeed, conscious beliefs are the exception, not the rule, as far as human doxastic states are concerned, and a naturalistic, realistic theory of knowledge that aspires to completeness has to take unconscious beliefs into consideration. This paper is the elaboration of such a theory of belief.