The Art of Fugue (Die Kunst der Fuge) is an incomplete work of unspecified instrumentation by J.S. Bach, written in the last decade of his life, and acting as a culmination of his experimentation with monothematic instrumental works. It consists of fugues and 4 canons, all variating a single principal subject, and ordered by increasing complexity. The order of the component pieces has been debated, as there are differences between the extant manuscript and the printed editions that appeared inmediately after Bach's death. Musical reasons have been invoked to propose differentorders for later publications and/or executions of the work. Contrapunctus XIV was left unfinished, and this has led to a great number of complex historical and theorical investigations on Bach's intentions regarding that last piece. Theories either reconstructing the ending or explaining why it was left like that have been advanced by scholars of different branches of the arts and science.
