This Handbook presents a theory of Business Interest Associations and fifteen empirical country by country case studies in the EU. The book is organized into three main parts. Part I develops a theory of business associations which centres on firm size as the key explanatory variable. Part II consists of country studies covering the EU-15, which are written along strictly comparable lines of analysis. Part III contains the cross-nationally comparative analysis. The book will make essential reading for researchers working in organization studies, industrial relations, industrial sociology and political science, as well as practioners in related fields.