This is the tenth edition of a classic work on child development by Ronald Illingworth (1909-1990), the renowned English paediatrician who was Professor of Child Health at the University of Sheffield. This book was first published in 1960, and Professor Illingworth revised it frequently. It was translated into several languages and is used throughout the world. Since the publication of the ninth edition of this book in 1987, a sea of changes has happened in the discipline of child development. To bridge this gap Dr. MKC Nair and Dr. Paul Russell have supported Professor Illingworth's extraordinary observations with contemporary evidence whenever available. In addition, they have included the current normative values in child development as well as cultural and societal influences on a developing child.