What do unions do and why do they do it? Do they seek to maximise profit for their members, or to obtain better working conditions that benefit society as a whole? Derek H. Aldcroft and Michael J. Oliver here provide one of the first sustained studies of the effects of union activities in terms of economic performance and the impact on the business world. From the rise of the British mass trade union movement in the 1870s to the present day, the book examines the main trends in union development and structure, and the core strategies unions have used to achieve their objectives: the use of strikes, work rules and restrictive practices; workers' attitudes to innovation; the wage bargaining process. Important assessments are made of the influence of these strategies on investment, innovation, economic growth, and the cost of structure and competitiveness of the UK economy.