Trade paperback. Profusely illustrated with diagrams, schematics and photographs. Stated first printing, October, 1980. Presenting cutting edge energy solutions for residential and commercial application for 1980-81, this vintage ‘exhibition’ edition covers not only conventional systems but alternative solutions such as solar, small hydroelectric applications, thermal storage technologies and a host of other innovations and manufacturers. No previous ownership marks. No spine crease. A clean, square, unmarked copy. Very good.