by William J. Cromie; illustrated with photographs and with diagrams and maps by Arthur Knapp Leo Schneider; illustrated with photographs and with drawings by Gustav Schrotter by Ira M. Freeman;illustrated with photographs and diagrams by Frank Ross; illustrated with photographs and diagrams by Helen Ross Russell; illustrated with photographys and with line drawings by Gene Garone by Don Dwiggins; illustrated with photographs and diagrams by Hal Hellman; illustrated wih photographs and diagrams