Vestibular schwannoma is the most common cerebellopontine angle tumor, and the retrosigmoid approach is the primary technique used by neurosurgeons for its microsurgical resection. Since the early twentieth century, significant advancements in neurosurgical techniques have been made, including the bilateral suboccipital approach and internal tumor decompression, pioneered by Harvey Cushing, and the unilateral suboccipital approach enhanced by Walter Dandy, resulting in reduced mortality and increased full tumor excision rates. Microsurgery and the retrosigmoid approach are the foundation of modern microneurosurgical treatment for vestibular schwannoma. In this chapter, the historical evolution of these interrelationships is reviewed.