The primary objective of the following study is not to indulge in the familiar passtime of ferreting out inconsistencies and fallacies in the thought of one of the keenest, noblest, and least expendable thinkers and doers of the nineteenth century. I want to bring out a certain motif in his philosophy of justice which comes to the surface only intermittently. The phrase which is most closely associated with this motif is that of the "accident of birth". It stands for the sum of those natural and social circumstances which are basically unfair and which our social reforms are called upon to remove or at least to relieve. The very fact that Mill appeals to this idea more often than any comparable philosopher seems to me sufficient reason for attention and acknowledgment.