I thought this was an excellent overview of different ethical systems. This lived up to my expectations. The authors obviously couldn't cover every ethical system ever devised, but I think they laid a really good groundwork to help me study some of these philosophers further.
(Philosophy for Dummies was a disappointment in that it was not so much an overview of philosophical thinking as it was a particular philosopher's argument for why the reader should choose his philosophical view. The authors of Ethics for Dummies had opinions that sometimes showed through, but I felt they were much more academic in their approach, giving you the information that you could utilize for developing your own judgment on those systems.)