Training, performance aids and documentation were the only kinds of support provided with most systems until online help started appearing in consumer software products. Integrating performance support product development allows the development of products that are consistent and complementary. Performance support can maximize usability by providing timely assistance to the user relevant to accomplishing their specific goals and solving problems which may occur along the way. Performance support includes all of the user-oriented materials, in addition to the user interface, that will support the user in learning and using the system. One of the major problems confronting developers and managers of performance support products is all of the different terminology used to represent similar design processes and outcomes. Many performance-centered design practitioners include user-centered design within performance-centered design, expand on user-centered design (UCD) or consider UCD different as Performance- Centered Design. The chapter also presents an overview of the key concepts discussed in this book.