Volume 4, the last in this popular DVD series, traces the organ’s development from the beginning of the nineteenth century to the present day with visits to France and Switzerland. The impact of changes in society, tastes, and musical styles, as well as technological advances are examined and illustrated with video images and musical examples. Works of J. S. Bach, Giuseppe Gherardeschi, Alexandre Guilmant, Max Reger, César Franck, Olivier Messiaen, Charles-Marie Widor and Jehan Alain are preformed by Ton Koopman, Marie-Claire Alain, René Saorgin, Ben Van Oosten, Louis Robilliard and Xavier Darasse.