Original sentence: During this era, his publishing house was publicly owned.He later criticized this novel as simplistic; nonetheless its publication convinced him to become a full-time writer.In 1951 he published his first book, Astronauci (The Astronauts); it was commissioned as juvenile SF and Lem included many references to the 'glorious future of communism' in it.Lem became truly productive after 1956, after"Polish October", when Poland experienced a new artistic wave.Lem finished a partly autobiographical novella Hospital of the Transfiguration (Szpital Przemienienia) in 1948, but it was not published until 1955 when he added a sequel written in the style of socialist realism
Edited sentence: He later criticized this novel (as well as several of his other early pieces, bowing to the ideological pressure) as simplistic; nonetheless its publication convinced him to become a full-time writer.However, during the era of Stalinism, all published works had to be directly approved by the communist regime.In 1951 he published his first book, Astronauci (The Astronauts); it was commissioned as juvenile SF and Lem was forced to include many references to the 'glorious future of communism' in it.Lem became truly productive after 1956, when the de-Stalinization period in the Soviet Union led to the "Polish October", when Poland experienced an increase in freedom of speech.Lem finished a partly autobiographical novella Hospital of the Transfiguration (Szpital Przemienienia) in 1948, but it was suppressed by the authorities until 1955 when he added a sequel more acceptable to the doctrine of socialist realism