This is an individual chapter of Theory of Constraints Handbook. Theory of Constraints is a highly concerned management development that runs contrary to traditional wisdom. TOC is best known in the Manufacturing and Distribution sectors where it came from, but services are the dominant sectors in many economies nowadays. The Professional, Scientific, and Technical Services (PSTS) sector is notable since many of its services are not repeatable, therefore making TOC much more difficult to apply. Nevertheless, it can be done. This chapter sums up how and why TOC has actually been adjusted for PSTS. It consists of applications for management of resources, jobs, company procedures, accounting, marketing, sales, method, and application. Amongst the benefits of TOC are quicker services, higher versatility, and a reasonable re-shuffling of management concerns for lucrative development. Simply mentioned, TOC makes constraints work for you instead of versus you. This chapter explains how specialists can begin with TOC for services, what researchers can contribute, and what students must know.