The response of clouds to global warming remains one of the major uncertainties in predictions of future climates that will result from human modification of the atmosphere. Progress is being made through improved parameterizations, explicit modeling of clouds with high spatial resolution, and new data from field experiments and satellite remote sensing. Work to confront climate models with cloud data is showing where the challenges lie and pointing to key improvements that can be made. The example of tropical convective cloud will be used to illustrate some of the problems and promise of cloud and climate change research. The explicit formulation of cloud physics and its interaction with dynamics and radiation remains a critical problem that calls for scientists in the mold of a young Peter Hobbs.