Over the past century scholars have commented on the incursion of organized political interests into the judicial process. Based on this work, we have accumulated a good deal of descriptive data about the type and frequency of interest group participation in judicial proceedings. Most of the existing research, however, is not theoretically informed but rather largely descriptive and idiographic. The largest barrier to the development of theoretically-oriented work is the lack of uniform, systematic, and comprehensive data, a failing this project intends to remedy. This collaborative project will create a multi-user database on the participation of organized interests as amici curiae ("friends of the court") in federal appellate courts and in state courts of last resort. For all cases containing at least one amicus curiae brief, the database will house information on the identity of the amici, their reasons for participating, and the position they urged the court to adopt. This database will be linked to existing databases including, the NSF-supported U.S. Supreme Court and the U.S. Courts of Appeals Databases. The database will be updated annually by the investigators.