The thesis gives a survey of theories relevant for understanding the problems in relations between lending banks and borrowing business firms.First a survey of comparative financial systems is given: The main types are bank-oriented (Germany, Japan, Sweden) and market-oriented systems (USA, GB). In the bank-oriented systems the risk exposure due to high-firm indebtedness is counteracted by trust in dense informal bank-firm networks. Market-oriented systems are characterized by arms-lenght bank-firm relations. Legal rules hinder the banks from active long-term relations with borrowing firms. Firms are financed on the anonymous markets.Sociology provides theory for analysis: social cohesion, norms, networks and trust. Institutional arrangements provide norms for societal cooperation that are enforced by culture. Traditional and modern society are used to exemplify two different ways of upholding social cohesion with emphasis on business relations.Concepts from neoclassical economic theory for analyzing these relations are: agency, transaction costs, contract, and asymmetric information.Game theory models strategic behaviour and conflict:; long-term relations can be interpreted as a way of bonding partners in an n-period Prisoners Dilemma game. A model is developed for analyzing bank-firm interaction for a firm in insolvency in a bank-oriented system.The thesis concludes with a speculative integrative model for the development of the business community. Three models are identified and named: the Oligarchy, the War-Lords and the Business(like) Rationality. The last model is an attempt to construct a model on the advantages from both The Oligarchy (inspired by the bank-oriented systems) and the War-Lords (inspired by the market-oriented systems).