A deal that both sides think they have struck can still fail at the threshold, either because too much was left open or because one party could not lawfully commit. This chapter begins with the essential elements of formation, then examines when vagueness or missing terms make an agreement void for uncertainty, the mechanisms — formulas, machinery and statutory default prices — that can rescue it, and the status of agreements to negotiate, lock-out agreements and dealings made 'subject to contract'. It then turns to capacity, working through minors and contracts for necessaries, which of their contracts are voidable and what remedies follow, before covering mental incapacity, intoxication and the position of companies acting beyond their objects. It closes with the formalities required for guarantees, including the line between a guarantee and an indemnity, and for contracts for the sale of land.
