I haven't come across a book on herbs yet that contains such concise, well organized, and detailed information. This is more than an encyclopedia, it is an essential how-to manual for any aspiring herbalist. For the seasoned veteran, it is still a worthy reference which combines traditional knowledge, like old names and special herbal terminology, with modern and up to date information, such as chemical constituents. While I personally think plant synergy is more important than the notion of "key medical ingredients", I appreciate that this book puts those facts forward and gives the reader the option of knowing.
Obviously this book cannot be a complete compendium, given its size, efficiency, and the fact that the world of herbs is incredibly diverse. Bartrum does, however, list many of the more well known herbs in western herbalism. My favorite part about it is that it not only includes medical information on the herbs, but also how to use them, such as in tinctures, salves, oils, etc., as well as recommended dosages according to the national herbalist institute in Britain.
I cannot fault this book whatsoever!