The principle here is based on the following diagram .....
Each of the two volumes contain exercises based on a series of 30 Angles concluding with ten fun and challenging solos putting the ideas into practice.

Book One introduces each angle with an exercise around the drums,
followed by a series of ten "Sketches" which are "loose" solos
guiding you through the possibilities of this concept.
Book Two is a comprehensive working of each Angle (one angle per page) using singles, doubles and paradiddles,
then ten dedicated solos of an advanced nature taking the concept
into an open ended co-ordinational love affair!