Beyond North Korea: Future Challenges to South Korea's Security. Edited by Byung Kwan Kim, Gi-Wook Shin, and David Straub. Stanford, Calif.: Walter H. Shorenstein Asia Pacific Research Center at Stanford University; Baltimore, Md.: Brookings Institution (distributor), 2011. 281 pp. $28.95 (paper).The US-South Korea Alliance: Meeting New Security Challenges. Edited by Scott Snyder. Boulder, Colo.: Lynne Rienner Publishers, 2012. vii, 293 pp. $59.95 (cloth).