Hornung is a top scholar in the field of Egyptology, yet he manages to avoid the condescending tone that many scholars fall victim to. John Baines' translation is precise and engaging, while a useful glossary is included at the back. For both the interested reader, and the serious scholar of ancient Egyptian religion, this would be the place to start. Basic concepts are discussed, such as the concept of god itself, the oft-perplexing issue of names & combinations of gods, depictions of gods, and the interaction between the living and divine.
Hornung's book "Idea into Image", a collection of lectures, is also highly recommended, but I think it is now difficult to find. It deserves to be reprinted too!