The "Album for the Virtuous" contains 25 short character pieces which are written to inspire you to play expressively on 4 timpani. They are consciously written at a moderate level of technical difficulty, so that young people with little experience on the timpani can be introduced to playing 4 timpani in a way which is musically interesting.
The metronome markings are to be understood as recommendations and can be varied or ignored according to technical level or personal taste.