Tadeusz Peiper (3 May 1891 – 10 November 1969) was a Polish poet, art critic, theoretician of literature and one of the precursors of the avant-garde movement in Polish poetry. Born to a Jewish family, Peiper converted to Catholicism as a young man and spent several years in Spain. He was a co-founder of the Awangarda krakowska ('Kraków Avant-garde') group of writers. In 1922, in the Second Polish Republic, he founded the Zwrotnica ('Railroad switch') monthly, devoted mostly to avant-garde movements in contemporary poetry. Although short-lived, the magazine (issued until 1923 and then briefly