Parts of this book were given as the Castle Lectures in Yale’s Program in Ethics, Politics, and Economics, delivered by Peter Singer at Yale University in 2013.

The Castle Lectures were endowed by Mr. John K. Castle. They honor his ancestor the Reverend James Pierpont, one of Yale’s original founders. Given by established public figures, Castle Lectures are intended to promote reflection on the moral foundations of society and government and to enhance understanding of ethical issues facing individuals in our complex modern society.