Read "Eau Naturel" - article about natural perfumery in LA Times Magazine, by journalist and crime-novelist (and perfumista!) Denise Hamilton (The Jasmine Trade, Damage Control).
The chart of natural-to-synthetic continuum that's in my perfumery course handbook, and is discussed at length in SmellyBlog's article "What Is Naturals?!" is mentioned there too, and if you haven't read it yet I encourage you to do so now.