Dr. Duke's book, The Green Pharmacy Herbal Handbook, contains accurate, no-nonsense information on many of the medically useful herbal preparations. His background in botany, provides excellent advise on uses and possible dangers.
For those herbs he includes there are lists of optimum dosages and warnings of possible contra-indications or dangers involved.
Over 180 herbs are described, in a quick to use format.
Even though it covers a small number of the herbs available for use, the ones he includes are important in treating a range of conditions.
I found it quite readable even for browsing in an evening, and emminently useful when faced with a sudden onset of a medical problem of the sort most treatable with herbs.