The Hollow Core: Private Interests in National Policy Makingby John P. Heinz; Edward O. Laumann; Robert L. Nelson; Robert H. Salisbury;The Politics of Interests: Interest Groups Transformedby Mark P. Petracca;Citizens, Political Communication and Interest Groups: Environmental Organizations in Canada and the United Statesby John C. Pierce; Mary Ann E. Steger; Brent S. Steel; Nicholas P. Lovrich;The Third House: Lobbyists and Lobbying in the Statesby Alan Rosenthal;Linking Citizens to Government: Interest Group Politics at Common Causeby Lawrence S. Rothenberg