North Korea has been among the most vexing and persistent problems in U.S. foreign policy in the post-Cold War period. The United States has never had formal diplomatic relations with the Democratic People's Republic of Korea (the official name for North Korea). Negotiations over North Korea's nuclear weapons program have consumed the past three U.S. administrations, even as some analysts anticipated a collapse of the isolated authoritarian regime. North Korea has been the recipient of well over $1 billion in U.S. aid and the target of dozens of U.S. sanctions. This report provides background information on the negotiations over North Korea's nuclear weapons program that began in the early 1990s under the Clinton Administration. As U.S. policy toward Pyongyang evolved through the George W. Bush presidency and into the Obama Administration, the negotiations moved from mostly bilateral to the multilateral Six-Party Talks (made up of China, Japan, Russia, North Korea, South Korea, and the United States). Although the negotiations have reached some key agreements that lay out deals for aid and recognition to North Korea in exchange for denuclearization, major problems with implementation have persisted. With talks suspended since 2009, concern about proliferation to other actors has grown. After Kim Jong-il's sudden death in December 2011, the reclusive regime now faces the challenge of transferring dynastic power to his youngest son, Kim Jong-un. Pyongyang had shown signs of reaching out in 2011 after a string of provocative acts in 2010, including an alleged torpedo attack on a South Korean warship that killed 46 South Korean servicemen and an artillery attack on Yeonpyeong Island that killed two South Korean Marines and two civilians. When Kim passed, the United States was reportedly on the verge of announcing an agreement on food aid and Pyongyang had indicated a willingness to freeze some parts of its nuclear program. The Obama Administration, like its predecessors, faces fundamental decisions on how to approach North Korea. To what degree should the United States attempt to isolate the regime diplomatically and financially? Should those efforts be balanced with engagement initiatives that continue to push for steps toward denuclearization, or for better human rights behavior? Should the United States adjust its approach in the post-Kim Jong-il era? Is China a reliable partner in efforts to pressure Pyongyang? Have the North's nuclear tests and alleged torpedo attack demonstrated that regime change is the only way to peaceful resolution? How should the United States consider its alliance relationships with Japan and South Korea as it formulates its North Korea policy? Should the United States continue to offer humanitarian aid? Although the primary focus of U.S. policy toward North Korea is the nuclear weapons program, there are a host of other issues, including Pyongyang's missile program, illicit activities, and poor human rights record. Modest attempts at engaging North Korea, including joint operations to recover U.S. servicemen's remains from the Korean War and some discussion about opening a U.S. liaison office in Pyongyang, remain suspended along with the nuclear negotiations.