Chapter 1 Introduction; Chapter 2 Waves of Union Structural Development, 1892–1987; Chapter 3 Promoting the Urge to Merge; Chapter 4 Mergers Within Industries; Chapter 5 Centralizing Union Structure and Leadership, 1892–1939; Chapter 6 The Tendency Towards Diversification, 1946–1987; Chapter 7 Conclusion; appendix Appendix;