Jazz HAP is a practical textbook on the basic principles of harmony, intended specifically for the jazz musician. In 60 lessons, divided into 12 chapters, it treats harmony and voice leading applied in jazz. An overview of the subjects is given in the table of contents.
Jazz HAP is employed as required subject matter at the jazz department of a number of conservatories in Holland and Belgium.
The book is mainly intended for those jazz musicians, both professional and amateur, who feel handicapped by their shortcomings at the keyboard. Specifically I have in mind vocalists - for them the piano is indispensable for many reasons - and horn players and bass players, who may wish to accompany their students, demonstrate the harmonic aspects of jazz music in their lessons, or deepen their own insight by means of the piano.
Learning to know your way around the keyboard is also a great help for ear training and for an understanding of music in general, besides, it's fun! It's also conceivable, that people who are familiar with traditional harmony might be interested to learn how chords are applied in the realm of jazz.
Jazz is, for the most part, tonal music. For this reason the material discussed in Jazz HAP predominantly follows the traditional concepts of harmony and voice leading. In my opinion, these have proven their value for centuries. However, Jazz HAP will almost immediately deal with seventh chords and chromaticism, both essential elements of jazz harmony.
In jazz HAP, special attention is paid to the relevance of embellishing chords. These are, to my opinion, slightly under-exposed in most harmony books. In jazz music, harmonic decorations are commonly used to enliven the harmonies under a melody. They present an opportunity to constantly vary the harmonization of a melody, without interfering with the global harmonic functions of the chords.
Those who want to study Jazz HAP without the help of a teacher should realize though, that the book is no bedtime reading, but a textbook on a fairly complex subject. Understanding the subject matter requires concentration and patience. Students should not be dismayed by the terminology and symbol notation, which are unavoidable in any discipline. Besides, they will quickly become familiar with these specifics.
For carrying out the exercises successfully, the accompanying text and the analysis of the examples are a little more advanced than strictly necessary. Students should not be discouraged when they do not immediately grasp something. In such cases it is best to read on and trust that things will become clearer on second reading. Especially in the beginning, a solid understanding of the examples is more important than brooding upon the accompanying analysis. In reading chord symbols, don't neglect the voice-leading rules, but do not let them get in your way. Usually it's better to develop some fluency and lustily play on, than to struggle with the best connection of the chords.
Finally, one last - not unimportant - advice: While playing the examples and exercises, never discard anything! Always listen closely to the sound of the chords and chord progressions. A slip, a 'wrong note', or an error might turn out to be an unexpected discovery.