The current human-caused extinction event gives cause for concern in that it threatens the nature we know and cherish. The threat is particularly serious because the replacement of species (speciation) is becoming increasingly less possible. In this climate, it is understandable that conservationists should direct their efforts largely towards species preservation, and this is indeed the emphasis of the majority of conservation projects. Even when emphasis is placed upon wider categories of living things such as habitats or ecosystems, this is often justified by a reference to the species that such systems sustain. It is, of course, difficult to talk of conservation without making reference to species, and indeed, in the earlier discussions of extinction, rarity and nativity, species were very much the focus of attention. However, in Chapter One I identified the key factor in the perpetuation of the nature we value, not as the preservation of species, but rather, as the opportunity for speciation. And in Chapter Five, I argued that this goal is best achieved through the perpetuation of wildness. So, whilst acknowledging the conservation position that species are important, I also suggest that they may not hold the central position in the overall conservation scheme that most conservationists assume them to have. But if species do not deserve to be central stage in the conservation arena, what position ought they to hold? In particular, if 'species' is of less importance than conservationists generally suppose, might there be more room for other categories of living thing whose relevance to conservation is currently overlooked? In seeking to assess the place 'species' has in nature conservation, we must begin by questioning whether – and if so, how – the category of species can be defined.