Book excerpt: The go-to resource for assessing and predicting functional abilities in persons with brain injury or cognitive decline has now been revised and expanded to reflect significant advances in the field. With a focus on key real-world capacities--independent living, vocational functioning, medication management, and driving--leading experts explore how individuals go about their daily lives, where and why disruptions occur, and potential opportunities for improving function. Strategies for direct assessment are reviewed, from standard neuropsychological tests to multimodal approaches and technology-based tools. Chapters also provide functional assessment guidance for specific neurological and psychiatric conditions: dementia, traumatic brain injury, depression, schizophrenia, and others. New to This Edition *Incorporates over a decade of technological and methodological innovations. *Chapter on theories and models of everyday functioning. *Chapters on naturalistic assessment, wearable sensors, ambulatory assessment, and virtual-reality-based tools. *Practical clinical implications are highlighted throughout.