The economic theory of contract is being reshaped in ways which resonate with the findings of socio-legal contract scholars and of industrial economists and sociologists in the Marshallian tradition, who emphasise the 'embeddedness' of organizations within their social and culturalenvironment. Contractual co-operation is seen as depending on institutional factors which serve to enhance 'trust', and arrangements which in the past were criticized as the product of collusion are being reassessed as potentially efficient responses to market failure. An active debate has begun on how instruments of public policy can best be deployed to arrive at an effective balance between co-operation and competition. This affects both the competitiveness of private sector organizations and the success of deregulatory reforms in the public sphere. Theseissues are explored within four main areas: developments in private-sector contracting; contract and organization in the public sector; the economics of contract law; and competitiveness and competition policy.