This chapter discusses the relevance of memory disorders in legal issues. The law of evidence has always been concerned with processes of human perception and memory. Mentally disordered witnesses, suspects and victims are vulnerable in different ways to giving unreliable testimony. Four reasons are put forward for voluntary false confessions: first, a pathological need to be infamous; secondly, a need to relieve guilt about matters unrelated to the confessed crime; thirdly, an inability to distinguish between fantasy and reality, as may be found in people with impaired 'reality monitoring' associated usually with severe mental illness; and, fourthly, an attempt to protect the real culprit. A defendant's right to testify on his own behalf may at times involve the use of hypnotically refreshed memory. Clinical reports prepared for legal proceedings need to be written with meticulous care in order to be credible and effective.