Hospital of the Transfiguration (in Polish: Szpital Przemienienia^[1]) is a book by Polish writer Stanisław Lem. It tells the story of a young doctor, Stefan Trzyniecki, who after graduation starts to work in a psychiatric hospital. The story takes place during the Nazi occupation of Poland in the Second World War.^[2]

The book is the first of a trilogy entitled Time Not Lost, and the only one of the three translated into English.

The book was adapted as a film of the same name (Szpital Przemienienia [pl]) in 1979, directed by Edward Żebrowski [pl]. 

Hospital of the Transfiguration is also available in paperback under ISBN 0-15-642176-3 (Mariner Books, 1991).