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.
Piron was a psychotherapist and taught from 1973 to 1994 in the psychology department at the University of Geneva in Switzerland. His French-language book Le défi des langues — Du gâchis au bon sens (The Language Challenge: From Chaos to Common Sense, 1994) is a kind of psychoanalysis of international communication. A Portuguese version, O desafio das linguas, was published in 2002 (Campinas, São Paulo, Pontes).
In a lecture on the current system of international communication Piron argued that "Esperanto relies entirely on innate reflexes"