Existing human beings stand in a unique relationship of asymmetrical influence over future generations. Our choices now can settle whether there are any human beings in the further future; how many will exist; what capacities and abilities they might have; and what the character of the natural world they inhabit is like. This volume, with contributions from both new voices and prominent, established figures in moral and political philosophy, examines three generally underexplored themes concerning morality and our relationship to future generations. First, would it be morally wrong to allow humanity to go extinct? Or do we have moral reasons to try and ensure that humanity continues into the indefinite future? Second, if humanity is to continue into the future, how many people should there be? And is it morally important whether they have lives that are of high quality or are just barely worth living? And third, how can we best make sense of the intuitive idea that by not taking action on climate change and preserving natural resources, we are in some way wronging future generations? This book was originally published as a special issue of the Canadian Journal of Philosophy.