Once money is exchanged for goods, the deal is completed. 一旦货币被换成商品，交易即告完成。

　　The transaction is simple: one party wants, another supplies. 这种交易简单明了：一方需要，另一方供给。

　　There is little scope for dispute, so a written contract can be dispensed with. 争议的余地很小，因而，成文合约可能被省去。

　　If one party is unhappy, he will take his business elsewhere next time. 如果一方不满意，他下次就会把业务带往他处。

　　Spot markets are thus largely self-policing. 因而，现货市场在很大程度上是自我管理。

　　They are well suited to simple, low-value transactions, such as buying a newspaper or taking a taxi. 它们非常适合买报纸和打的等简单和低价值的交易。

　　Things become trickier when the parties are locked into a deal that is costly to get out of. 当参与者陷入放弃成本高昂的交易中时，事情就变得棘手了。

　　Take a property lease, for instance. 以房屋租赁为例。

　　A business that is evicted from its premises might not quickly find a building with similar features. 一家从其经营场所中被赶出来的公司不可能很快找到一处特点类似的建筑。

　　Equally, if a tenant suddenly quit, the landlord might not find a replacement straight away. 同样，如果租户突然退出，房主也不可能立即找到代替者。

　　Each could threaten the other in a bid for a better rent. 每一方都可能以更好的租金要挟对方。

　　The answer is a long-term contract that specifies the rent, the tenure and use of the property. 答案是一份标注出租金、租期和产权使用的长期合约。

　　Both parties benefit. 两方双双获益。

　　But for many business arrangements, it is difficult to set down all that is required of each party in all circumstances. 但是，对于许多商业安排而言，敲定为每一方在任何情况下所要求的一切就难了。

　　In such cases, formal contracts are by necessity “incomplete” and sustained largely by trust. 在这类例子中，正式合约势必是“不完整的”，而且主要是靠信任来维持。

　　An employment contract is of this type. 雇佣合同即是这种类型。

　　It has a few formal terms: job title, work hours, initial pay and so on, but many of the most important duties and obligations are not written down. 它有很多正式条目：工作职位、工作时间、初始工资等等。但是，最重要的责任和义务大都没有被写入。

　　It is thus like a “mini-society with a vast array of norms beyond those centred on the exchange and its immediate processes”, wrote Mr Williamson. 因而，它就像一个“规范繁多的微型社会”。

　　Such a contract stays in force mostly because its breakdown would hurt both parties. 这类合约之所以有效，主要是因为违约会对双方造成伤害。

　　And because market forces are softened in such a contract, it calls for an alternative form of governance: the firm. 而且，由于市场力量在这类合约中被软化了，它呼唤一种替代性的管理形式：公司。

　　One of the first papers to elucidate these ideas was published in 1972 by Armen Alchian and Harold Demsetz. 最早阐述这些观点的论文中的一篇是由阿门·阿尔奇安(Armen Alchian 又译艾智仁)和哈罗德·德姆塞茨(Harold Demsetz)在1972年发表的。

　　They defined the firm as the central contractor in a team-production process. 他们将公司定义为团队生产过程中的中心签约者。