With the emergence of mass higher education, many national governments have identified a diverse higher education system as a policy objective. Diversity is seen as good because it supposedly increases the range of choices for students, matches the education provided to the needs and abilities of individual students, enables and protects specialization within systems, and meets the demands of an increasingly complex social order. However, little is known about the internal dynamics of higher education systems working for or against particular levels of diversity. The present volume attempts to further our understanding of processes affecting diversity by addressing them from a theoretical and empirical perspective in a comparative setting. The theoretical part of the book outlines three distinct but complimentary perspectives. Burton Clark discusses the effects of continued specialization at the disciplinary level and concludes that this will stimulate diversity at the system's level. Guy Neave draws attention to the possible homogenizing forces of the nation state and of the emerging supra-national structures in Europe. Frans van Vught also emphasizes the effects of the (policy) environment on institutional and system diversity, and specifies under what conditions this influence will lead to decreasing diversity. The empirical part of the book contains eight country studies. These analyses provide detailed insights into the processes that have affected differentiation in these countries. They also provide the basis for an analysis of the theoretical arguments from a comparative perspective. The concluding chapter is an analysis of the conditions which influence change within higher education institutions and systems, and what the effects of these changes are in terms of diversity.