This highly practical book is an accessible and grounded handbook for addressing challenging behaviour in children and adults with intellectual or developmental disabilities (IDD), including autism. It recognises that challenging behaviour does not appear out of nowhere and is meaningful for the person exhibiting it. Behaviour can be communicative and an important signifier of underlying sensory or environmental issues. Focusing on a person-centred approach throughout, the book has advice and strategies for working with the client's families, support staff and professionals. It also presents best practice for analysing and addressing challenging behaviour in various settings such as schools, hospitals and the home, all while stressing the need to keep the human story at the heart of any assessment and intervention. Each chapter features questions for discussion or reflection and exercises for the reader to complete. Informal, frank and free of jargon, this is indispensable for professionals, parents, and anyone working with people with intellectual disability or autism.