This chapter explains how voluntarily assumed obligations arising at common law, and also in equity, may not be unilaterally changed by the obligor thereto without the prior assent of the obligee. Wesley Hohfeld's jural relations of claim-right/duty; power/liability; privilege/no-right; and immunity/disability are employed to demonstrate that the identity of an obligee to an obligation (‘to whom’ the obligation is owed), is just as much a part of the specificatin of the obligation as, say, the specification as to ‘what’ is to be performed.