The general purpose of this book differs from those of most of the works found traditionally in the field of political philosophy. Firstly, the present approach is in no way prescriptive or normative, as the interest centres on explication rather than an evaluative assess ment of this, that or another type of arrangement, or act. 1 It will be clear that I am in complete disagreement with Gewirth when he claims that "The central concern of political philosophy is the moral evaluation of political power. " It seems obvious that the under standing of political and social forms of life, and a fortiori of political power, must come before its evaluation. This cannot be provided by moral assessment alone. Thus an analytical or explicative approach which promotes such understanding must come first, and must be the "central concern" of the appropriate philosophical discipline. This is not to say that moral assessment is illegitimate, nor even that it cannot be one of the concerns of political philosophy, but it is to deny that it can be central, even though it might be somebody's central interest. To the extent to which this book is successful it will provide an argu mentin my favour - if the job can be done, obviously it is of primary importance. But we should not assume that it cannot be done unless we can show that there is no separate sphere of political and/or social phenomena.