This thesis is an inquiry into the ethical aspects of the advocate's function within the adversarial system. Specifically, it addresses the question whether that function is inherently unethical in so far as it subordinates truth to client interest. While many of the issues dealt with are common to both civil and criminal proceedings, the inquiry concentrates mainly on the role of the advocate in criminal proceedings and particularly on that of defence counsel. The advocate's role is examined within the context of the principles underlying the adversarial system; in particular, the relationship in that system between the pursuit of truth and its recognition of other values associated with individual freedom and autonomy. The thesis is sequentially structured as follows