Orchestras have traditionally been built around top-down control. Some have, however, taken a different path—one that allows musicians to make decisions. This chapter begins by posing some of the big questions that arise when that happens. The pertinent basic features of orchestras as organisations are also explained. These companies span the worlds of musical performance and enterprise. These worlds are themselves changing, and the challenges of establishing or running an orchestra today are different from those of the late nineteenth or early twentieth centuries, when many of today’s orchestras got their start. The chapter also explains why this book zooms in on the experience of organisations that were founded in recent decades and that face the particular tests of modern orchestral life. The chapter concludes with an overview of the book. Reading this chapter will help understand why musicians’ controlling their orchestras is a phenomenon worth studying.