The Organic Gardener's Handbook

If you only buy one book on organic gardening this should be the one - a comprehensive yet concise guide that tells the gardener all they need to know about organic cultivation. 

From the basics of climate, geology and soils, through an explanation of plants and their needs to the planning and planting of a variety of vegetables and edible plants, yield charts, month by month planting, companion planting and moon gardening, and so on and so on. This book gives much sound advice to the novice and wealth of information to the experienced organic gardener all in a handy format.