This book provides practical knowledge for the necessary differentiated sleep medicine diagnostics and an optimal short-, medium-, and long-term therapy based on it. Sleep disorders are one of the most common health issues. Over half a million people in Germany regularly take sleeping pills. Additionally, complaints from non-restorative sleep can significantly impair the performance and quality of life of those affected, often with long-term health consequences. The teaching and learning book for exam preparation for the qualification certificate in Somnology from the DGSM and the additional designation in Sleep Medicine offers advice for daily work in clinics and practices. It covers fundamentals, pathophysiology, diagnostics, differential diagnostics, therapy standards, and alternatives. Everything that is important, common, and clinically relevant is presented with practical tips, case studies, and questions for exam preparation.