Claude Piron, also known by the pseudonym Johán Valano, was a Swiss psychologist, Esperantist, translator, and writer. He worked as a translator for the United Nations from 1956 to 1961 and then for the World Health Organization. He was a prolific author of Esperanto works. He spoke Esperanto from childhood and used it in Japan, China, Uzbekistan, Kazakhstan, in Africa and Latin America, and in nearly all the countries of Europe. Source: Wikipedia (en)