The theory of the firm consists of a number of economic theories that explain and predict the nature of the firm, company, or corporation, including its existence, behaviour, structure, and relationship to the market. Firms are key drivers in economics, providing goods and services in return for monetary payments and rewards. Organisational structure, incentives, employee productivity, and information all influence the successful operation of a firm in the economy and within itself. As such major economic theories such as Transaction cost theory, Managerial economics and Behavioural theory of the firm will allow for an in-depth analysis on various firm and management types. Overview In simplified terms, the theory of the firm aims to answer these questions: Existence. Why do firms emerge? Why are not all transactions in the economy mediated over the market? Boundaries. Why is the boundary between firms and the market located exactly there in relation to size and output variety? Which transactions are performed internally and which are negotiated on the market? Organization. Why are firms structured in such a specific way, for example as to hierarchy or decentralization? What is the interplay of formal and informal relationships? Heterogeneity of firm actions/performances. What drives different actions and performances of firms? Evidence. What tests are there for the respective theories of the firm? Firms exist as an alternative system to the market-price mechanism when it is more efficient to produce in a non-market environment. For example, in a labor market, it might be very difficult or costly for firms or organizations to engage in production when they have to hire and fire their workers depending on demand/supply conditions. It might also be costly for employees to shift companies every day looking for better alternatives. Similarly, it may be costly for companies to find new suppliers daily. Thus, firms engage in a long-term contract with their employees or a long-term contract with suppliers to minimize the cost or maximize the value of property rights. Background The First World War period saw a change of emphasis in economic theory away from industry-level analysis which mainly included analyzing markets to analysis at the level of the firm, as it became increasingly clear that perfect competition was no longer an adequate model of how firms behaved. Economic theory until then had focused on trying to understand markets alone and there had been little study on understanding why firms or organisations exist. Markets