An Agricultural Testament. London & New York: Oxford University Press, 1940. Describes Howard's early crusade to restore humus to industrial farming.
The Soil and Health. New York: Devin Adair, 1947. Also published in London by Faber & Faber, titled Farming and Gardening for Health or Disease. A full development of Howard's theme that humus is health for plants, animals and people.
Howard, Louise E. The Earth's Green Carpet. Emmaus: Rodale Press, 1947. An oft-overlooked book by Howard's second wife. This one, slim volume expresses with elegant and passionate simplicity all of the basic beliefs of the organic gardening and farming movement. See also her Albert Howard in India.
Kevan, D. Keith. _Soil Animals. _London: H. F. & G. Witherby Ltd., 1962. Soil zoology for otherwise well-schooled layreaders.
King, F.H. Farmers of Forty Centuries or Permanent Agriculture in China, Korea and Japan. Emmaus: Rodale Press, first published 1911. Treasured by the organic gardening movement for its description of a long-standing and successful agricultural system based completely on composting. It is a great travel/adventure book.
Koepf, H.H., B.D. Petterson, and W. Shaumann. _Bio-Dynamic Agriculture: An Introduction. _Spring Valley, New York: Anthroposophic Press, 1976. A good introduction to this philosophical/mystical system of farming and gardening that uses magical compost inoculants.
Krasilnikov, N A. _Soil Microorganisms and Higher Plants. _Translated by Y.A. Halperin. Jerusalem: Israel Program for Scientific Translations, 1961. Organic gardeners have many vague beliefs about how humus makes plants healthy. This book scientifically explains why organic matter in soil makes plants healthy. Unlike most translations of Russian, this one is an easy read.
Kuhnelt, Wilhelm. _Soil Biology: with special reference to the animal kingdom. _East Lansing: Michigan State University Press, 1976. Soil zoology at a level assuming readers have university-level biology, zoology and microbiology. Still, very interesting to well-read lay persons who are not intimidated by Latin taxonomy.
Minnich, Jerry. _The Earthworm Book: How to Raise and Use Earthworms for Your Farm and Garden. _Emmaus: Rodale Press, 1977. This book is a thorough and encyclopedic survey of the subject
Minnich, Jerry and Marjorie Hunt. _The Rodale Guide to Composting. _Emmaus, Pennsylvania: Rodale Press, 1979. A very complete survey of composting at home, on the farm, and in municipalities. The book has been through numerous rewritings since the first edition; this version is the best. It is more cohesive and less seeming like it was written by a committee than the version in print now. _Organic Gardening and Farming _magazine may have been at its best when Minnich was a senior editor.