The development of modern neurosurgery in the Netherlands, which took place in the 1920s, was highly influenced by the personal involvement of both Harvey Cushing and Walter Dandy, each in his own way. For the present article, the authors consulted the correspondence (kept at the Cushing/Whitney Medical Library in New Haven and the Alan Mason Chesney Medical Archives in Baltimore) of Cushing and Dandy with their Dutch disciples. The correspondence provides a unique inside view into the minds of both neurosurgical giants. After the neurologist Bernard Brouwer had paved the way for sending the Dutch surgeon Ignaz Oljenick overseas, Cushing personally took the responsibility to train him (1927–1929). On his return to Amsterdam, Oljenick and Brouwer established the first neurosurgical department in the country. Encouraged by Oljenick's favorable results, a number of Dutch general surgeons started asking Cushing for support. Cushing strategically managed and deflected these requests, probably aiming to increase the advantage of Oljenick and Brouwer. However, the University Hospital in Groningen persisted in the plans to establish its own neurosurgical unit and sent Ferdinand Verbeek to the US in 1932. Although staying at Cushing's department initially, Verbeek ultimately applied to Walter Dandy for a position of visiting voluntary assistant, staying until the end of 1934. Verbeek and Dandy became lifelong friends. On his return to Groningen, Verbeek started practicing neurosurgery, isolated in the northern part of the country. He relied on the support of Dandy, with whom he kept up a regular correspondence, discussing cases and seeking advice. Dandy, on his part, used Verbeek as the ambassador in Europe for his operative innovations. At the beginning of World War II, Oljenick had to flee the country, which concluded the direct line with the Cushing school in the Netherlands. After Dandy's death (1946), Verbeek continued practicing neurosurgery following his style and philosophy. By the time Verbeek died in 1958, the strong American influence on everyday practice of Dutch neurosurgeons had been established.