Galbraith's principal theoretical contribution is foreshadowed in American capitalism and unfolds more clearly into view in his trilogy The Affluent Society, The New Industrial State and Economics and the Public Purpose. His thesis is that the economic ideas that once explained a world of poverty have not adjusted to a world of affluence dominated by the modern corporation. His main themes are the concentration of economic power in the large corporation and the social and environmental imbalance that results from the large corporation. Galbraith attempts to tease out the implications of the uneven development of modern affluence and outlines an emancipatory case for social change.