This volume contains the output of country research undertaken in Poland by Piotr Kozarzewski and Richard Woodward under the international comparative project "Secondary Privatization: the Evolution of Ownership Structures of Privatized Enterprises". The project was supported by the European Union's Phare ACE Programme 1997 (project P97-8201 R) and was coordinated by Barbara Baszczyk from the Center for Social and Economic Research (CASE) in Warsaw, Poland. The support of the ACE Programme made it possible to organize the cooperation of an international group of scholars (from the Czech Republic, France, Poland, Slovenia and the U.K.). The entire project was devoted to the investigation of secondary ownership changes in enterprises privatized in special privatization schemes (i.e., mass privatization schemes and MEBOs) in three Central European countries - the Czech Republic, Poland and Slovenia. Through a combination of different research methods, such as secondary analysis of previous research, analysis of legal and other regulatory instruments, original field research, statistical data base research and econometric analysis of individual enterprise data, the project aimed to investigate the scope, pace and trends in secondary ownership changes, the factors and barriers affecting them and the degree of ownership concentration resulting from them. The authors begin with a general discussion of MEBOs in Poland and go on to analyze ownership changes in a sample of such companies. First, they present the initial ownership structures created at the time of privatization and the evolution of those structures through 1999, and then go on to analyze the factors behind these changes and the relationships between the evolution of ownership structures on the one hand and economic performance and corporate governance on the other. We hope that the results of this research will be of great interest for everyone interested in the little-researched question of what has happened to companies after privatization in transition countries.