Gerre Hancock has long been renowned for his extraordinary improvisations, and has for many years taught the art of improvisation at classes and workshops across the United States. Now he has codified and organized his teaching into a book which carries the organist from the scale through the fugue, covering on the way interludes, hymns, hymn preludes, sonata form, canon, and more. Written in an informal style and illustrated with musical examples and exercises, this book opens wide the door to musical and technical skill.