Give some stream of consciousness and then the answer. Between Shades of Gray, a New York Times Bestseller, is the debut novel of American novelist Ruta Sepetys. It follows the Stalinist repressions of the mid-20th century and follows the life of Lina as she is deported from her native Lithuania with her mother and younger brother and the journey they take to a labor-camp in Siberia. It was nominated for the 2012 CILIP Carnegie Medal and has been translated into more than 27 languages.

Answer this question: when does between shades of gray take place?
The important part for answering this question is: It follows the Stalinist repressions of the mid-20th century and follows the life of Lina as she is deported from her native Lithuania with her mother and younger brother and the journey they take to a labor-camp in Siberia.
Therefore, the answer is the mid-20th century.