Hashimoto's thyroiditis is one of the most common autoimmune diseases of our time—and also one of the most misunderstood. In medical practice, it is often reduced to hypothyroidism, which can apparently be reliably treated with hormone replacement therapy. But this view is too narrow. Despite “normal” lab values, many sufferers experience persistent fatigue, cognitive impairment, emotional dysregulation, and systemic complaints for which there has been no satisfactory explanation to date. For the first time, this book consistently takes Hashimoto's thyroiditis seriously for what it is: a chronic, systemic autoimmune disease with complex neuro-immune-endocrine effects. Based on current international research, it combines immunology, endocrinology, neuroscience, and clinical medicine into an integrative disease model. It not only presents established findings, but also highlights new perspectives that critically question existing diagnostic and therapeutic paradigms. Particular attention is paid to the limitations of laboratory diagnostics, the long-term consequences of chronic inflammation, the neuropsychological effects of the disease, and the reasons why many sufferers remain symptomatic despite guideline-based therapy. The work highlights new research approaches, epigenetic and environmental factors, and discusses the consequences for modern medical care. Bremen University Press has published over 5,500 specialist books in various languages since 2005. February 2026