What is rehabilitation? This Report defines rehabilitation as “a set of measures that assist individuals who experience, or are likely to experience, disability to achieve and maintain optimal functioning in interaction with their environments”. A distinction is sometimes made between habilitation, which aims to help those who acquire disabilities congenitally or early in life to develop maximal functioning; and rehabilitation, where those who have experienced a loss in function are assisted to regain maximal functioning (2). In this chapter the term “rehabilitation” covers both types of intervention. Although the concept of rehabilitation is broad, not everything to do with disability can be included in the term. Rehabilitation targets improvements in individual functioning – say, by improving a person’s ability to eat and drink independently. Rehabilitation also includes making changes to the individual’s environment – for example, by installing a toilet handrail. But barrier removal initiatives at societal level, such as fitting a ramp to a public building, are not considered rehabilitation in this Report. Rehabilitation reduces the impact of a broad range of health conditions. Typically rehabilitation occurs for a specific period of time, but can involve single or multiple interventions delivered by an individual or a team of rehabilitation workers, and can be needed from the acute or initial phase immediately following recognition of a health condition through to post-acute and maintenance phases. Rehabilitation involves identification of a person’s problems and needs, relating the problems to relevant factors of the person and the environment, defining rehabilitation goals, planning and implementing the measures, and assessing the effects (see figure below). Educating people with disabilities is essential for developing knowledge and skills for self-help, care, management, and decision-making. People with disabilities and their families experience better health and functioning when they are partners in rehabilitation (3–9). The rehabilitation process Identify problems and needs Assess eects Relate problems to modi‑able and limiting factors De‑ne target problems and target mediators, select appropriate measures Plan, implement, and coordinate interventions Source: A modified version of the Rehabilitation Cycle from (10). Rehabilitation – provided along a continuum of care ranging from hospital care to rehabilitation in the community (12) – can improve health outcomes, reduce costs by shortening hospital stays (15–17), reduce disability, and improve quality of life (18–21). Rehabilitation need not be expensive. Rehabilitation is cross-sectoral and may be carried out by health professionals in conjunction with specialists in education, employment, social welfare, and other fields. In resource-poor contexts it may involve non-specialist workers – for example, community-based rehabilitation workers in addition to family, friends, and community groups. Rehabilitation that begins early produces better functional outcomes for almost all health conditions associated with disability (18–30). The effectiveness of early intervention is particularly marked for children with, or at risk of, developmental delays (27, 28, 31, 32), and has been proven to increase educational and developmental gains (4, 27).