As discussed in Chapter 1, the focus of this book is on design for aging adults, a critically important and growing user group. The central goals of the book are to provide illustrative case studies of design problems across of variety of domains that have been undertaken by the Center for Research and Education on Aging and Technology Enhancement (CREATE) and to describe the tools and techniques used to address these challenges. In this chapter, we present an example of a software system developed for older adults by the CREATE team, the Personal Reminder Information and Social Management System (PRISM). PRISM was intended to support social connectivity, prospective memory, knowledge about topics and resources, and entertainment. The PRISM system encompassed a software program, a training package, and user support tools (user manual and help card). The development of PRISM involved the use of most of the human factors usability tools and methods discussed in Chapter 4 and highlighted in the case studies described in other chapters. Our intent in this chapter is to present a case study that begins with the inception of a system to evaluation of the system in a multi-site field trial to illustrate how an iterative, user-centered design approach can be used to design a system that accounts for the needs, abilities, and preferences of a diverse older adult user group.