Jazz Improvisation for Keyboard Players by Dan Haerle is a straightforward, no-nonsense improvisation series. It deals with creating melodies, using the left hand, pianistic approaches to soloing, scale choices for improvisation and much more. Book 1 is introductory level and covers the very basics. Book 2 covers intermediate concepts. Book 3 covers advanced concepts.
The complete version includes all three volumes in one book.
Book 1 - Chapter 1: Creating Melodies
Book 1 - Chapter 2: Using The Left Hand
Book 1 - Chapter 3: Pianistic Approaches To Soloing
Book 1 - Chapter 4: Chord Progressions For Study
Book 2 - Chapter 1: Developing Melodies
Book 2 - Chapter 2: Further Use Of The Left Hand
Book 2 - Chapter 3: Basic Scale Choices
Book 2 - Chapter 4: Rhythmic Conception
Book 2 - Chapter 5: Different Treatments Of The II-V-I Progression
Book 3 - Chapter 1: Factors Affecting Scale Choices
Book 3 - Chapter 2: Approaches To Harmonic Conception
Book 3 - Chapter 3: Melodic Implications Of Tri-Tone Substitution
Book 3 - Chapter 4: Superimposition Of Scale Forms
Book 3 - Chapter 5: Scale Generation Of Unconventional Voicings