The editors synthesize ten case studies sponsored by the National Academy of Public Administration that relate stories of congressional intervention and suggest, in sum, a new theory of congressional-executive relations. Arguing that Congress cannot be dimissed as simply a troublesome meddler in agency programs or as an inattentive bystander in its oversight role, Gilmour and Halley draw from these case histories the surprising conclusion that Congress in facts acts regularly, with the executive branch, as a powerful co-manager of policy outlines and program details. Each case study is organized to examine the process and the results - for policy, for the institutions involved, for management, and for congressional-executive relations - when Congress intervenes in the administrative domain. Addressing specific issues in policy areas including transportation, environment, health, energy, defense and foreign affairs, a team of scholars and professionals explores these illustrative cases within a common framework that allows for identification and comparison of cross-case patterns.