How do I get from A (minor) to B flat (major)? The Theory of Modulation is a kind of musical roadmap that not every student is able to master with facility. Doris Geller’s concise book is based on her many years of teaching experience. With the help of many music examples, the author explains the various modula-tion techniques and challenges the student to experiment with the material on the piano at all times. In the end, the student will not only be able to "run” through the circle of fifths like a virtuoso, but, in Geller’s opinion, will have learned something even more important: "Whoever has learned how to modulate has also become knowledgeable in harmony and harmonic analysis - a by-product that should not be underestimated!”