We identify and investigate the basic 'hold-up problem' which arises whenever each party to a contract has to pay some ex-ante cost for the contract to become feasible. We then proceed to show that, under plausible circumstances, a 'contractual solution' to this hold-up problem is not available. This is because a contractual solution to the hold-up problem typically entails writing a 'contract over a contract' which generates a fresh set of ex-ante costs, and hence is associated with a new hold-up problem.