Christopher Brickell was director general of the Royal Horticultural Society from 1985 to 1993, president of the International Society for Horticultural Science from 1998 to 2002, and is currently chairman of the International Commission for the Nomenclature of Cultivated Plants. An editor-in-chief of DK's The American Horticultural Society Encyclopedia of Gardening, he is also a frequent lecturer, writer, and adviser to numerous organizations. His comprehensive knowledge of ornamental garden plants and his active involvement with many aspects of horticulture have brought him many awards. Dr. H. Marc Cathey, US editor-in-chief, a renowned research horticulturist and President Emeritus of the American Horticultural Society, spent 37 years at the USDA. His studies of the effects of light, temperature, pollutants, and chemicals on plants have benefited all gardeners. Dr. Cathey was the fourth Director of the US National Arboretum (1981-1991) and was instrumental in the creation of the USDA Plant Hardiness maps (1990 and 2003) and the AHS Plant Heat Zone map (1997). He is a frequent guest on national TV and is currently a commentator on National Public Radio.Cathey, H. Marc is the author of 'American Horticultural Society A-Z Encyclopedia Of Garden Plants ', published 2004 under ISBN 9780756606169 and ISBN 0756606160.