Increasingly, judges have recognized the value of a neutral outside observer -- the special master -- in overseeing the process through which prison and jail systems remedy constitutional violations. Court and corrections officials estimate that there are approximately 90 masters active in jails and prisons across the United States. The costs of a mastership are considerably less than those of bringing a prison system into compliance. Special masters are likely to become a permanent feature of the corrections landscape. The services of a master are often necessary if court-ordered changes are to be put into place in a timely and even-handed manner. The only successful mastership is the one that institutionalizes reforms so that they will be maintained over the long term. Courts and masters, plaintiffs and defendants, still need to find the means to speed up the process of getting a system into compliance and releasing the master from his responsibilities. The effectiveness of a master will depend on a large extent on his ability to create an atmosphere of trust.