In the US alone, over four and a half million people have cognitive disabilities. Except for deficiencies of mnemonic and executive capabilities, many of them have the potential to live a more independent life. In this book, the author describes a design approach and an example system aimed at providing support to those missing abilities in a socio-technical environment. The system, MAPS, consists of two technical components: a script design tool that allows a caregiver to create, store, edit and reuse scripts of multimedia prompts to guide users thru tasks, and a PDA-based prompter that plays those scripts for persons with cognitive disabilities. The process of technology adoption was also studied as the MAPS system was put in use doing real-life tasks in home, shopping, and employment environments. By extending human-computer interaction (HCI) frameworks, theories, and perspectives, this research shows new ways of using traditional HCI in the design and use of prompting systems. More importantly, this study presents a set of heuristics to aid in the general design of assistive technology with an aim of preventing technology abandonment.