Over-two thirds of the U.S. population is allergic to poison oak, poison ivy, or a related plant. These and many other common plants in our homes, fields, and gardens are irritants that cause misery to many. But surprisingly, there has never been a general guide to help raise awareness of them--and to help avoid them. This new book reviews the history, occurrence, classification, toxicity, and health aspects of all the major allergenic and irritant species.