This introductory field guide is much, much better than the old Little Golden Guide" that beginning Lepidoptrists (butterfly lovers) have relied on in the past. I wish I had had the new First Guide version a kid! It shows accurate color drawings of the most common species, along with the food plants and, in some cases, the other life stages such as larvae and pupae.
I especially like the fact that it includes so many moths -- not just the showy ones like Cecropias and Lunas that beginners dream about but seldom find -- but some of the little gray and brown ones, too, such as might show up any evening around your yard light. Plus, I finally found out that a grayish day-flying moth with a metallic-blue body that I see around here all the tiime is callled a "Southern Ctenucha."
As a Master Gardener volunteer, I currently recommend this to 4H-ers (and adults, too) who are just getting started in entomology. It's easy to use, and the light pocket size makes it nice for children to carry on field trips. Buy it along with "First Guide to Caterpillars" in the same series (which I have also reviewed here on Amazon).