This chapter provides a comprehensive overview of the surgical principles for managing middle ear cholesteatoma, primarily from the perspective of the German school of otology. It covers the definition, pathogenesis, and classification of both congenital and acquired cholesteatomas. The text details essential diagnostic procedures, including clinical history, otoscopy, audiology, and radiological imaging. Key surgical techniques are discussed, emphasizing the principles of complete cholesteatoma removal, ensuring proper drainage, and preserving or reconstructing function. A central theme is the critical decision-making process between canal-wall-up and canal-wall-down mastoidectomy, with detailed criteria for each approach. The chapter also addresses ossicular chain reconstruction, tympanic membrane repair, management of reoperations for residual or recurrent disease, and handling of potential complications such as labyrinthine fistula and facial nerve exposure. Finally, special considerations for treating pediatric and elderly patients are outlined.