This is the book I go to when I want to find out about the traditional medicinal properties of an herb. It's especially helpful for warning about toxicity and contraindications.

It includes the latin name for the herb, many of the common names and a description of the plant parts. The medicinal properties require a bit of cross referencing to the section that tells you what "febrifuge" and all the other "technical terms" means ("an agent that reduces or eliminates fever").

I'm always amazed by the people that start using an herb (even in a tea or "food" form) extensively without checking in such a book. For instance, Rosemary can raise blood pressure. Before falling madly in love with everything Rosemary, I'd probably want to find out a little more about the herb if I had a problem with high blood pressure.

There are not a whole lot of citations given for "proof" about most of the claims, but the author is a widely recognized expert with an extensive education on the topic. His point is not to prove but to get his knowledge across.

There's even a nice section on non-medicinal purposes of herbs, like for dyes, cosmetics, beverages, etc.