This is the introduction to the Journal of Global Ethics symposium on Peter Singer's The Most Good You Can Do: How Effective Altruism is Changing Ideas About Living Ethically. It summarizes the main features of effective altruism in the context of Singer's work on the moral demands of global poverty and some recent criticisms of effective altruism. The symposium contains contributions by Anthony Skelton, Violetta Igneski, Tracy Isaacs and Peter Singer.