Requires time and very careful analysis to understand fundamentals. Well worth the effort because understanding allows us to answer questions about ontology, epistemology, physics, metaphysics, logic, ethics, evolutionary, origins of universe and life, consciousness and theology: all concepts so important required for critical thinking/philosophy. I’m a neurologist. College graduate degree, chemical engineering. Would be harder to understand book without that educational background. One of my favorite books. Believers in a personal God may not like atheist perspective.