The development of practical, man-portable radio sets for communication between companies and battalion headquarters, and later between platoons and companies, was central to the character of World War II infantry fighting. It enabled units to employ flexible, coordinated tactics, allowing their commanders to exploit success, call in supporting fire, or limit the costs of failure. However, the new man-pack radios were still immature and infantry commanders also had to employ other means, from wire-linked field telephones to the most basic of all - a soldier carrying a message. This concise guide to a vital and fascinating aspect of World War II tactics explains the equipment and practice of the US, British, Soviet, German, and Japanese armies. It is illustrated with many wartime photos, and with color plates showing everything from telephones and radios to flags and flare pistols, and how they were used. Book jacket.