The ice giant planets, Uranus and Neptune, represent an important and unexplored class of planets. Mostof our detailed information about themcomes from fleeting looks by the Voyager 2 spacecraftin the 1980s.Voyager,and ground-based work since then, found that these planets, their satellites, rings, and magnetospheres, challenge our understanding of the formation and evolution of planetarysystems. We also now knowthat Uranus-Neptune size planetsare common around other stars. These are some of the reasons ice giant exploration was a high priority in NASA’smost recent Planetary Science Decadal Survey. In preparation for the next Decadal Survey,NASA, with ESA participation,conducted a broad study of possible ice giant missions in the 2024 –2037 timeframe. This paper summarizes the key resultsof the study,and addressesquestionsthat have been raised by the science communityand in a recent NASA review. Foremost amongstthese are questions about the science objectives, the science payload, and the importance of an atmospheric probe. Theconclusions ofthe NASA/ESA study remain valid. In particular, it is a high priority to sendan orbiterand atmospheric probeto at least one of the ice giants, with instrumentationto studyall components of an ice giant system.Uranus and Neptune are found to be equally compelling as science targets. The two planets are not equivalent, however, and each systemhas thingsto teach us the other cannot. An additional mission study is needed to refine plans for future exploration of these worlds.