Jean Guillou (1930–2019) was organist at the Parisian church of Saint Eustache from 1963 to 2015, succeeding André Marchal. For many years, he commuted from Paris to Zürich, where he taught master classes in organ performance, improvisation, and composition, and consulted on the building of new organs, some of radical design. He composed more than 100 works for organ, made more than 100 recordings, and presented literally thousands of recitals in Europe, the U.S., and Asia. The Toccata, Op. 9 was composed in 1963 and is representative of Guillou’s dense, chromatic, and highly rhythmic style. Three themes are presented and used to build tension leading toward the percussive finale.