The social commentary in "Murder on the Orient Express" is also noteworthy. Christie was writing in a period of great social change, and the novel reflects the tensions and anxieties of the time. The characters on the train represent a microcosm of society, with its rigid class hierarchies, social norms, and prejudices. The novel critiques the artificiality and superficiality of the upper class, revealing the empty, indulgent lives of the wealthy and powerful.