During the last decade the endoscopic endonasal approach (EEA) to the skull base has become a very powerful method to add to the array of neurosurgical technologies. This volume provides a broad overview of the role of transnasal approaches in a wide spectrum of skull base diseases. It starts with a historical perspective of the evolution from the microscope to the endoscope in endonasal surgery and then explores in depth the principles and techniques of the various methods. Discussed are topics based on anatomical boundaries: pituitary fossa to the suprasellar space to the cavernous sinus, clivus and the anterior cranial fossa. Access to the infratemporal and posterior fossae via both the endoscopic endonasal and the retrosigmoid approaches are reviewed. In addition, the critical topic of reconstruction following ‘minimally invasive’ skull base surgery and finally the learning curve and complications associated with the applications of these new and exciting approaches are discussed. This volume will provide the latest knowledge to help neurosurgeons, otolaryngologists, head and neck surgeons as well as craniofacial surgeons understand the applications and practice of this important technique.