This chapter reviews evidence for the dissociation between implicit and explicit knowledge in the various syndromes. It discusses whether the findings in the different syndromes can be explained by some common mechanism, and what light the findings shed on the implicit-explicit distinction in normal people. Much of the evidence for a distinction between implicit and explicit processing in neuropsychological disorders comes from studies of prosopagnosia. The amnesic syndrome is characterised by normal perceptual, linguistic, and intellectual functioning together with an inability to remember explicitly recent events and new information. Implicit/explicit dissociations have also been noted in a number of other neuropsychological syndromes, although the evidence is far more fragmentary. A number of theoretical accounts have already been discussed in relation to specific syndromes. Most of the neuropsychological evidence can be interpreted as showing that knowledge can be below a subjective threshold of awareness.