Peterson's is good, I would wait on it though because a new volume should be coming out very soon. According to my info, it is actually a few months late, so I would think any day now.
Current Therapy in Oral & Maxillofacial Surgery by Bagheri is another fairly comprehensive, virtually brand new text and it is relatively cheap.
Either of those should be plenty of info for a non-OMFS practitioner looking to bulk up their knowledge or a student looking to prepare for the road to residency.
If just wanting to get a very basic knowledge, I agree with GTFO..