this book is a collection of some of my essays on interrelated aspects of Kant’s theory of human nature. With one exception, each of the essays was written after the publication my book Kant’s Impure Ethics: From Rational Beings to Human Beings (Oxford University Press, 2000). In that book, I examined the underexplored second or impure part of his ethics, an empirical part which does not always fit easily with the better-known first or pure part, but one which Kant himself viewed as a necessary and important constituent of his project in practical philosophy. The essays included in the present volume continue and deepen avenues of exploration initiated in Kant’s Impure Ethics—i.e., they explore different branches of his empirical work on human nature, with special reference to the connections between this body of work and his ethical theory.