Inflammatory Bowel Disease (IBD) is a complex and multifaceted condition that affects millions of people worldwide. This comprehensive textbook provides an in-depth exploration of critical yet often-overlooked aspects of IBD, aiming to fill a significant gap in the current literature. It offers a unique focus on pediatric populations, discussing body composition and the impact of lactose intolerance and small intestinal bacterial overgrowth (SIBO). The book navigates through the evolution of diagnostic pathways in IBD, highlighting both traditional methods and novel approaches that have emerged with advancements in technology and our understanding of the disease. This section serves as a valuable guide for clinicians, helping them make informed decisions about the most appropriate diagnostic tools for their patients. It then delves into therapeutic drug monitoring, an essential aspect of personalized medicine. It provides insights into how this approach can optimize drug therapy, improve patient outcomes, and reduce the risk of adverse effects. The textbook also identifies predictors of non-response to conventional treatment, providing insights into when a shift in strategy might be necessary. Understanding these predictors is crucial as it can guide clinicians in tailoring treatment plans, potentially preventing unnecessary disease progression and complications. Lastly, it discusses surgical interventions in IBD, a crucial consideration when medical management falls short. It provides a comprehensive overview of the various surgical options, their indications, potential complications, and the decision-making process that leads to surgery. This textbook is designed to serve as an invaluable resource for clinicians, researchers, and students. It aims to enhance the understanding and management of IBD, ultimately contributing to improved patient outcomes and quality of life. With its practical, evidence-based information, this book is a must-read for anyone seeking to deepen their knowledge of IBD.