The development of inexpensive DNA sequencing technologies has revolutionized all aspects of biological research. The proliferation of plant genome sequences, in conjunction with the parallel development of robust tools for directed genetic manipulation, has given momentum and credibility to the goal of understanding several model plants as the sum of their parts. A broad inventory of the functions and interrelationships of the parts is currently under way, and the first steps toward computer models of processes have emerged. These approaches also provide a framework for the mechanistic basis of plant diversity. It is hoped that rapid progress in this endeavor will facilitate timely responses to expanding demand for food, feed, fiber, fuel, and ecosystem services in a period of climate change.