Book excerpt: Hydroponics, the method of growing plants without soil, presents a feasible alternative to conventional farming in areas which are short on water supply and limited in agricultural soil. This book will serve as an indispensable guide for students in the agriculture sciences, for agriculture instructors and soilless-culture farmers. It provides up-to-date information on optimal plant nutrition, deficiencies and toxicities of nutrients, plant growth media, optimal root environment, environmental control, carbon dioxide requirements, saline conditions and use of sewage in soilless culture. Other topics include economic aspects of hydroponics, new growth methods and an outlook for the future.