I really had difficulty classifying this book. For the most part, it is a guide to some of the more common non native plants that have naturalized as well as plants that are already listed as being noxious weeds. it does not appear to include any species introduced in the past 20 years or so that have proven to be aggressive or capable of outcompeting native flora. There are a few native species intermixed however the author didn't quite differentiate between what was invasive and what wasn't. This publication has value for some of the line drawings however it is somewhat dated in my opinion.