Energy plays a fundamental role in most natural systems, and in the physical theories we use to describe them.  Energy also plays a central role in human civilization; energy-related issues are at the core of many current political and economic challenges, and our choices related to energy use and technologies will have profound impact on the future of Earth and humanity over the coming centuries.  This colloquium will focus on ways in which the physics of energy systems can illuminate important real-world questions and on how energy and energy-related issues can be incorporated into science curricula.  The speaker and colleague Robert Jaffe have been teaching an undergraduate course for students in all disciplines at MIT on "The Physics of Energy" for the last 10 years, and have recently completed a comprehensive award-winning text on energy science based on the course.