The management world knows by now that to be effective in the workplace, an individual needs high emotional intelligence. What isn't so well understood is that teams need it, too. Citing such companies as IDEO, Hewlett-Packard, and the Hay Group, the authors show that high emotional intelligence is at the heart of effective teams. These teams behave in ways that build relationships both inside and outside the team and that strengthen their ability to face challenges. High group emotional intelligence may seem like a simple matter of putting a group of emotionally intelligent individuals together. It's not. For a team to have high EI, it needs to create norms that establish mutual trust among members, a sense of group identity, and a sense of group efficacy. These three conditions are essential to a team's effectiveness because they are the foundation of true cooperation and collaboration. Group EI isn't a question of dealing with a necessary evil--catching emotions as they bubble up and promptly suppressing them. It's about bringing emotions deliberately to the surface and understanding how they affect the team's work. Group emotional intelligence is about exploring, embracing, and ultimately relying on the emotions that are at the core of teams.