Intertemporal choices are decisions with consequences that play out over time. These choices range from the prosaic--how much food to eat at a meal--to life-changing decisions about education, marriage, fertility, health behaviors and savings. Intertemporal preferences also affect policy debates about long-run challenges, such as global warming. Historically, it was assumed that delayed rewards were discounted at a constant rate over time. Recent theoretical and empirical advances from economic, psychological and neuroscience perspectives, however, have revealed a more complex account of how individuals make intertemporal decisions. We review and integrate these advances. We emphasize three different, occasionally competing, mechanisms that are implemented in the brain: representation, anticipation and self-control.