In this chapter, various circumstances surrounding the formation of contract will be considered from a promissory viewpoint.

Traditionally, the Common law and mixed legal systems have been against the idea that any liability of a promissory type might exist between negotiating parties before formation of contract, though that has not precluded duties arising between the parties based upon tort. By contrast, as will be seen, German law has a developed notion of culpa in contrahendo, a type of liability which appears to lie in the interstice between contract and tort. Increasingly however, even the Common law is recognising that some situations (such as breach of conditions of tender) merit liability, and promise can provide a rationale for such liability. The making of a so-called ‘firm offer’ is another circumstance where some systems consider that duties ought to arise, though this view is not shared by English law or South African law; in those systems where liability does arise, promise can again be used to explain the origin of the duties. Promises of reward and options are also considered: again, where these are legally enforced, promise provides an attractive solution to explain their basis in law. Letters of intent and the question of error in the formation of contract are trickier: the simple idea of promise does not provide an obvious solution to the problems that each raises, and some consideration is given as to how best therefore to characterise the results in cases raising those issues.