Book excerpt: Assistive technologies have become increasingly important for people with disabilities in recent years. This book is the result of over a decade of research into computational approaches to assistive technology. Its chapters are based on a number of graduate theses, successfully completed over the past dozen or so years under the supervision of Kanlaya Naruedomkul of Mahidol University in Bangkok, Thailand and Nick Cercone of York University, Toronto, Canada. Some applications in the chapters use Thai language examples, but the techniques employed are not restricted to any single language. Each chapter is based on the Ph.D. work of a former or current student, suitably updated and presented for interested readers. The book is divided into four sections. Following an introduction, which includes a review of assistive technology products, part two covers applications, and includes chapters on alternative sign text MT for language learning, lexical simplification using word sense disambiguation and detecting and rating dementia through lexical analysis of spontaneous speech. Part three deals with theories and systems, and includes: granules for learning behavior, rough sets methods and applications for medical data and multimedia support systems as assistive technology for hearing impaired students. Part four presents a conclusion which includes a look into the future. Although this book is not a comprehensive treatise on assistive technology, it nevertheless provides a fascinating look at recent research, and will be of interest to all those whose work involves the application of assistive technologies for people with disabilities.