The Senior Service program starts with setting-up exercises which open the chest, gently stimulate the heart, and start the blood coursing through the system, and follows with progressive walking, a little hill-climbing, and, later in the development, with some weight-carrying exercises. The system renews the resistive force of the body, tones up the muscles, opens the chest cavity so that the heart and lungs have more room and the breath is deeper and better, gives general exercise to the various muscles which have become more or less atrophied from disuse, and brings about a marked improvement in the mental outlook and in the animal spirits. The system is a combination of setting-up exercises with outdoor work, all carefully and precisely laid out after twenty years of experience in conditioning men. It should be followed absolutely, not partially or occasionally. It is far from severe. Its strength lies in the cumulative effect rather than in any special effort at any one time. It should be said that a mental effort is requisite in this course as well as the physical one. The correlation between mind and muscle must be re-established. The man must become master of his body once more and retain that mastery. Certain suggestions are also given specifically as to living--none of them irksome, but quite essential if the full result of the work is to be attained. This was the first experiment of its kind, and hence it has proven of especial interest. There are plenty of cases of individuals taking up exercise in one form or another and benefiting somewhat by it; but when twenty to one hundred men in a group have engaged in this Senior Service work, the result has proven remarkable in every instance. The question seems to be simply this: If you are over military age and wish to renew your youth, and are willing to pay the price by devoting some three or four hours a week to a scientifically tested system, and can secure a score of other men to do it with you, you can be absolutely assured of success. Well, isn't it worth it? INDIVIDUAL AND GROUP ACTION Thousands of men are beginning to realize what all this means. My mail for the last six months has been full of the inquiry. Men of forty are rapidly awakening and are eager to devote these few hours to the task of keeping fit, and so increasing their efficiency. At the same time they are preventing these horrible and untimely punishments at the hand of Mother Nature. Now there are two methods by which a man may still be young at sixty. One is an exceedingly hard route for most men to travel--namely, the individual practice of this scientifically tested formula and patient persistence in it. The other is by group action. The latter is far easier and its results are doubly effective. However, as in some cases group action may be impossible, this book furnishes the data for individual practice as well.