Herb reference

In your opinion, what is a good starter book on medicinal herbs for a newbie?

James A. Duke's books.

Examples-
Duke, J. A. 2000. The Green Pharmacy Herbal Handbook: Your Comprehensive Reference to the Best Herbs for Healing. Emmaus, Pennsylvania: Rodale Press
Duke, J. A. 2009. The Green Pharmacy Guide to Healing Foods. Emmaus, Pennsylvania: Rodale Press.

Not books, but these two Databases are indispensable for finding info on specific herbs (medicinal/culinary)

http://www.purplesage.org.uk/profileindex.htm
This link is for searching by common name, but if you click a link, you can search by Latin name;

http://www.herbs2000.com/herbs/1menu.html

Hope this helps you (or anybody else).