The idea for this book took shape during the final two years of my endocrinology specialty training, driven by a desire to share practical learning from real-world clinical experience. Thyroid disorders are common, yet their presentation and management can often be nuanced and challenging. This case series aims to reflect that clinical reality. The book brings together a collection of interesting and thought-provoking cases covering a broad spectrum of thyroid disorders. Most cases begin with a focused clinical question, followed by a structured case presentation, discussion, and most importantly clear key learning points to consolidate practical take-home messages. Having started this work as a senior specialty registrar and now practising as a Consultant in Diabetes and Endocrinology, two years into post, I have gained a deeper appreciation of the clinical questions that arise in everyday practice and the uncertainties clinicians often face. This perspective has shaped the way each case is presented and discussed, with an emphasis on pragmatic, evidence-based decision-making. This book is not intended to be exhaustive. The primary aim has been to keep the content concise and to the point, with emphasis on key learning points and meaningful discussion. It is hoped that this format will make the book particularly useful for specialty trainees, endocrine specialist nurses, and other healthcare professionals involved in the care of patients with thyroid disease. This book is dedicated to our mentors, teachers, trainees and patients The work has been undertaken entirely on a voluntary basis, without sponsorship, and any proceeds from the sale of this book will be donated to the British Thyroid Foundation.