In the fascinating world of endocrinology, scientific knowledge and technology have advanced greatly in recent years. Alongside, the ability to diagnose, treat, and manage various endocrine disorders has progressed too. The goal of this textbook is to provide an up-to-date, comprehensive, yet accessible resource for understanding and managing endocrine disorders in dogs. The book is divided into two parts. The first part adopts a problem-oriented approach to the most common clinical and laboratory abnormalities in dogs with endocrine diseases. This section, full algorithms that guide step by step veterinarians in diagnostic evaluation and setting up the treatment, serves as a quick reference guide in clinical situations. The second part focuses on endocrine diseases. Each chapter starts with the basic anatomy and physiology of the specific endocrine glands, followed by detailed discussions on clinical signs, diagnostic methodologies, and management strategies. Chapters are richly supplemented with videos available through QR codes, boxes, tables, algorithms, charts, imaging studies, and illustrations.