In recent years, distributed computing and monitoring technologies have gained a lot of interest in the cross-disciplinary field of healthcare informatics. This introductory chapter reveals the growing need for timely detection of numerous health threats of older people, who are challenged by various chronic and acute illnesses and are susceptible to injuries. First, we give a concise overview of the relevant terms, which are often used for representing state-of-the-art technologies and research fields dealing with monitoring of older patients. Second, we guide the readers through the contents of this book, which are intended for both geriatric care practitioners and engineers, who are developing or integrating monitoring solutions for older adults. Then, we provide a summary of notable worldwide smart-home projects aimed at monitoring and assisting older people, including geriatric patients. The underlying aim of these projects was to explore the use of ambient and/or wearable sensing technology to monitor the well-being of older adults in their home environments.