This book focuses on human behavioural processes and describes them from an interdisciplinary perspective. It introduces readers to the main theories and approaches in the field of organisational development and change (ODC), and discusses their relevance and purpose with a clear focus on improving how readers perceive and handle change. The book is tailor-made for business students without any background in the humanities, helping them to conceptualise organisational development and change, and to practically organise interventions to increase organisational effectiveness. The book’s goal is to help future managers and consultants recognise and handle the ‘full situation’, which includes purposes, people and relationships. Furthermore, it elaborates on those theories and instruments that can deliver real benefits to real people working in real fuzzy and complex circumstances, and includes several practical cases focusing on the role of the interventionist.