We study the moral hazard problem with general upper and lower constraints M on compensation. We characterize the optimal contract and show existence and uniqueness. When minimizing costs for given effort, a principal harmed by M will pay according to M on some range of outcomes; when M reflects limited liability or a minimum wage, the contract is option-like. When the principal also chooses effort, a principal harmed by M might nonetheless never pay according to M. This cannot occur if the cost of inducing effort in the standard principal-agent problem is convex, for which we provide sufficient conditions related to the informativeness of outcome about effort.