The Investigation (original title Śledztwo) is a science fiction/detective/thriller novel by the Polish writer Stanisław Lem. The novel incorporates a philosophical discourse on explanation of unknown phenomena. It was first published in 1958 in Przekrój magazine (issues 698-711) and in 1959 as a book by the Publishing House of the Ministry of National Defense (Wydawnictwo Ministerstwa Obrony Narodowej). Source: Wikipedia (en)