The position which we have now reached is as follows. We began by seeking to vindicate a universal approach to moral theory as against the contextualism which has become popular among some proponents of environmental ethics. This was necessary in order to permit the possible development of a moral theory of the relations between human beings and the non-human beings with which we share the planet which, if valid, would be meaningfully addressable to all moral agents, whatever their cultural context. We then spent time attempting to defend the view that non-human organisms are all morally considerable. Specifically, we aimed to show that there is no good reason to exclude the class of non-sentient organisms from that category. We endeavoured to defend the reasonableness of a theory of differential moral weight as applied to various kinds of organism. We then argued that our moral responsibilities towards non-human organisms are not simply those of humaneness, but encompass requirements of distributive justice, in spite of what appear to be insurmountable objections to the idea that beings which are solely moral patients can be proper recipients of such justice. We then examined some eminent theories of distributive justice with respect to the purely human case to ascertain whether any of them could accommodate the idea of distributive justice towards the non-human. Two candidates proved to be incompatible with such a notion. However, latterly we sought to show that the liberal theory of justice which has emerged from the Rawlsian matrix is capable of encompassing justice towards the non-human and of justifying some constitutional provisions to secure the claims of the non-human to their fair share of environmental resources.