Howard has been called the father of modern composting, for his refinement of a traditional Indian composting system into what is now known as the Indore method. He went on to document and develop organic farming techniques, and spread his knowledge through the UK-based Soil Association, and the Rodale Institute in the US. His 1940 book, "An Agricultural Testament", is a classic organic farming text. He emphasizes the importance of maintaining humus, keeping water in the soil, and the role of mycorrhiza. It was his first book aimed at the general public, and is his best popularly known work. However his 1931 book "The Waste Products of Agriculture", based on 26 years of studying improved crop production in Indian smallholdings, is considered by some as his most important scientific publication. His 1945 book "Farming and Gardening for Health or Disease" was also intended for a general audience, and was republished in 1947 as "The Soil and Health: A Study of Organic Agriculture". Howard's work influenced and inspired many farmers and agricultural scientists who furthered the organic movement, including Lady Eve Balfour (the Haughley Experiment, "The Living Soil") and J.I. Rodale (Rodale Institute).