Murder on the Orient Express is a classic locked-room mystery. Discuss how this influences the detective’s investigative approach, considering the book’s emphasis on psychological investigation. Highlight concrete examples of Poirot embracing this approach.

Discuss the significance of red herrings to a mystery, tracing at least two examples and explaining how they function to disorient Poirot and the reader.

What purpose do Bouc and Dr. Constantine serve? Why does the author bother to include these passive characters? Consider their role as it pertains to the reader.