PERHAPS the tradition in the elementary law of contracts most thoroughly grounded in the minds of law students is the general proposition that an agreement between A and B cannot be sued upon by C, even though C would be benefited by its performance. It always was, with Harvard law students at all events, an article of faith that rights founded on contract belong to the person who has stipulated for them; and that even the most express agreement of contracting parties would not confer any right of action on the contract upon one not a party thereto.
[See the full post at: Privity of Contract by Jesse Warren Lilienthal]