Growth is a measurable index of health. The study of growth is of paramount importance in pediatrics. A pediatrician needs to be well versed with the knowledge and practice of measurement of growth and its proper assessment to enable him to find out if the child is growing adequately or not in reference to individual performance capability and also the community. The basic need in studying growth is to know and use appropriate, scientifically sound and statistically relevant methods. If methods are not identical, it becomes impossible to compare and understand the difference of performance of different children with regard to national and international reference standards. Growth and development is a continuous process from fertilization till maturity. Besides genetic factors, growth is influenced by nutrition. Illness and social economic and psychological environment. To study in totality all aspects of his fascinating subject is the sailing through an ocean which has no other shore. In our humble endeavor, we have touched upon the important aspects of physical growth from the intrauterine period till adolescence, the methods of assessment as well as neurobehavioral development of newborn through infancy to childhood along with its abnormalities and early intervention. Growth and development comprise the basic science in the field of pediatrics. Pediatricians owe responsibility for care of the child and should thus be familiar with the methods of study and assessment of growth, their normal patterns and milestones of normal development, thus enabling them to recognize any deviations from norm at the earliest. This should enable us to detect deficiencies or disorders and to give appropriate and timely attention and care. Child development is fascinating subject to many clinicians and nonclinical investigators. But unfortunately what is taught in books and what is practiced does not match, so a wholesome practicable scientific approach towards understanding the evolution of development is the need of the hour. Pediatricians have always concentrated on the developmental syndrome, but the large majority of the vulnerable newborns with biological and environmental risks for developmental delay are getting ignored. Early intervention through these delicate periods of neuroplasticity is often rewarded with a normal or near normal outcome. For the older children also, problems of motor, visual, language, perceptual and writing difficulties need to be addressed with great care and concern for assessment and intervention. The Child Development Center (CDC) in Thiruvananthapuram with the patronage from Government of Kerala is successfully practicing towards this aspect as a pioneer institute for long years. The lesson on child development in this book is largely based on the experience from this institute and the like researches through the world. To understand the growth and development of children in our country, to propagate the knowledge acquired and to sensitize to community, an institute of Growth and Development have been formed with national and international collaboration by interested pediatricians from Vivekananda Institute of Medical Sciences, Kolkata, Child Development Center (CDC), Thiruvananthapuram and the Department of Pediatric Endocrinology, the Royal Manchester Children Hospital, UK. This book is an endeavor of the institute towards this aim. viii Growth and Development of Children and Adolescents This book has been divided into 2 sections – Section 1 deal with physical growth (Chapter 1-21) and Section 2 is concerned with development and its problems (Chapter 22-31). We hope that this book will fulfill the need of the students in pediatrics both undergraduate and postgraduate as well as the researchers in the field of human growth and development.