Efforts to better connect scientific research with people and organizations involved in environmental decision making are receiving increased interest and attention. Some of the challenges we currently face, however—including complex questions associated with climate change—are unlike most of the environmental issues encountered in the past because of their scale and scope as well as the fact that they have no easily agreed upon solutions. Focused research on the intersections between environment and society has provided substantial insight into dynamics of large-scale environmental change and the related impacts on people, natural resources, and ecosystems, yet our ability to connect this research to real-world decision making remains limited. Addressing these complex environmental problems requires broad cooperation between scientists and those who may apply research results in decision making, but there are few templates for guiding the growing number of scientists and practitioners now engaging in this kind of cooperative work. This handbook offers a set of heuristics for carrying out collaborative work between scientists and practitioners. These heuristics were derived from research that examined the direct experiences of water resources professionals and climate researchers who have been working to integrate science and practice.