Born in Kraków on the 3rd of February, 1906. He spent his childhood in Limanowa and then attended the Jesuit Secondary School in Chyrów, and the Classical Secondary School in Nowy Sącz. From 1929 he studied at the Department of Philosophy of the Jagiellonian University, and then at the Department of Law of the same institution. In 1926-31 he also studied economy at the Higher School of Commerce and Industry. After a short period of bank employment he launched a career of a publicist in Kraków magazines of M. Dąbrowski’s press syndicate, including one of the most influential newspapers – the “Ilustrowany Kurier Codzienny”, where he dealt with international problems and especially with subjects connected with Germany. In the columns of that magazine two of his novels were issued in numbers. From 1938 he was its correspondent in Bucharest. In September 1939 he had to escape from Poland due to, among others, the criticism of Germany included in his articles. For one year he was the press attaché of Polish embassy in Bucharest. After it was wound up, Mieroszewski, by way of Istanbul and Cyprus, got to the Middle East in April 1941, where he joined the Polish Independent Carpathian Brigade (SBSK) and served in its Department of Culture and Press. From 1943 he performed the same duties in the whole Polish II Corps and co-edited the magazines “Parada”, “Ku wolnej Polsce”, and “Orzeł Biały”; it was in that period that he became acquainted with Jerzy Giedroyć. After the war and demobilization, he left Italy in December 1946 and settled down in London in the following year. He never left England, keeping up only limited contacts with the Polish exiles living there. Initially, he collaborated with “Wiadomości”, and “Orzeł Biały”, and from 1949 – with the Paris “Kultura”, becoming its regular correspondent in the following year under the pen–name ‘Londyńczyk’ (‘Londoner’). He propagated the notions of a possible evolution of the Communist system, of the necessity to support its internal transformations as we as the democratic forces emerging in Poland, and of the need for cooperation with the other nations subjugated by the Soviet Communism, and particularly with Poland’s eastern neighbours, demanding, on that account, that the Poles give up their former eastern territories in favour of Lithuanians, Byelorussians, and Ukrainians. He translated G. Orwell’s 1984 into Polish, as well as M. Djilas’s The New Class. His own works include Ewolucjonizm (1964), Polityczne neurozy (1967), Modele i praktyka (1970), and Materiały do refleksji i zadumy (1976). He died in London on the 21st of June, 1976.