A closed knight\u27s tour of a chessboard uses legal moves of the knight to visit every square exactly once and return to its starting position. In 1991 Schwenk completely classified the m x n rectangular chessboards that admit a closed knight\u27s tour. In honor of the upcoming twentieth anniversary of the publication of Schwenk\u27s paper, this article extends his result by classifying the i x j x k rectangular prisms that admit a closed knight\u27s tour
