On 21 November 2007 the grand and elegant Delegates Hall of the Hungarian Parliament was the scene of the opening of a conference to discuss some of the most pressing issues of the day, those related to our unending thirst for energy, its environmental consequences, and the challenges that these bear on security. Over the next 3 days scientists, parliamentarians and their guests confronted, challenged, teased and cajoled each other in a NATO Advanced Research Workshop (ARW) entitled Energy and Environmental Challenges to Security, affirming that knowledge and public service hold the keys to solving our greatest challenges. The magnitude of the security challenge was confirmed while this volume was being prepared. In mid-2008, the International Energy Agency issued a report concluding that US$45 trillion would be needed over the next half century to prevent energy shortages and greenhouse gas emissions from undermining global economic growth. But lest such large numbers cause us all to shrug, this volume brings attention to some of the more manageable aspects of the environment and energy security challenge - from addressing conflict resources such as illegal timber that contribute to corruption and regional instability, to means and mechanisms to enable the diversification of energy supplies, to environmental risk reduction strategies for particular installations. The participants in the Hungarian Parliament building were atypical for a NATO Advanced Research Workshop.