The purpose of this chapter is to critically review current theoretical perspectives on the representation, production, and modification of simple and complex movement sequences. This is followed by an empirical example illustrating the development of a sequence structure for a complex movement sequence and examples of practice conditions that facilitate or interfere with the development and maintenance of the sequence structure. It is our position that the sequence structure provides the fundamental basis for efficient, effective, and durable performance and transfer under some task constraints, but also can impede transfer and relearning under others.