One of the key scientific challenges is the puzzle of human cooperation. Why do people cooperate with one another? What causes individuals to lend a helping hand to a stranger, even if it comes at a major cost to their own well-being? Why do people severely punish those who violate social norms and undermine the collective interest? Edited by Paul A.M. Van Lange, Bettina Rockenbach, and Toshio Yamagishi, Trust in Social Dilemmas carefully considers...