In 1920, he published a scientific article on the Kula Ring, perhaps the first documentation of generalised exchange. In 1922, he earned a doctorate of science in anthropology and was teaching at the London School of Economics. That year his book "Argonauts of the Western Pacific" was published. It was widely regarded as a masterpiece, and Malinowski became one of the best-known anthropologists in the world. For the next two decades, he would establish the London School of Economics as Europe's main centre of anthropology. He became a British citizen in 1931. In 1933, he became a foreign member of the Royal Netherlands Academy of Arts and Sciences.