This book is similar to Steve Hagen's book on Buddhism. Like Khema, Hagen is also a Westerner and a long-time teacher of Buddhism. Neither book focuses on historical detail, biography, academic aspects of the Buddha's teachings, or the Buddhist universe (though Khema touches on it more than Hagen does). The focus in both is on how to live a Buddhist life.
Khema focuses much more than Hagen on the importance of meditation.
The concept that the reason for acting morally and compasionately in Buddhism is that this will ultimately decrease desire, in both yourself and others (a bizaare-sounding statement taken out of context) is neatly explained here. That desire is the cause of suffering, one of the four Noble Truths, is of course explained in both books. But Khema makes it clearer why the Buddhist should act in a 'moral' way.
Despite this, I do find Hagen's book more lucid, despite his tendency to repeteat himself.