It is an interesting paradox of international law that the right of self-defence is considered to be an inherent right of all states. Th at a state has the right to defend itself from attack from others is unarguable and is refl ective of man’s basic instinct for survival. Yet whilst the principle of the right of self-defence is so clear and unchallenged, its legal defi nition and scope of application has been the subject of much debate and controversy. Hence the paradox—clear and unchallenged yet giving rise to controversy and confusion. It is this debate and controversy to which Murray Colin Alder seeks to bring some clarity in his very interesting book.