1. The most obvious reason why children wish to work is that they "want to earn money," to spend as they like. Here is a great opportunity and a considerable danger. The opportunities are to help support the family, to learn self-reliance, to gain in efficiency, to appreciate the sacrifices made by parents, to purchase innocent pleasures, and to save toward a college education. The dangers are that children may become too commercially minded, grasping, even dishonest, make dull playmates, and become stunted in character for lack of play and wholesome stimulus to the imagination. If you will analyze these dangers you will find that they are all the results of overdoing good things. The old rule of the Greeks, "Nothing too much" is the golden rule to measure perfect commercial relations between parents and children. 2. But far more important than money making is character making. And therefore one of the principles of this book is to suggest in a thousand ways that money making may go too far. For example, I would encourage boys to gather and sell nuts, but not to take nuts from a neighbour's trees without permission nor destroy young trees whose future crops belong to a future generation of boys. I encourage trapping but urge the use of humane traps to avoid cruelty. I encourage the gathering and selling certain wild flowers, if abundant, but warn against the danger of exterminating species, or of robbing the public of pleasure. I have gone over all of the things that children do out of doors and have tried to select the best occupations. I have studied the worst things they do and have suggested their opposites--constructive work that earns money, develops character, or preserves public property. For example, instead of collecting birds' eggs I suggest methods of attracting birds, building houses for them, and providing food and protection from enemies. 3. The book is addressed to the citizens of nineteen hundred and twenty. Will not busy boys and girls make better citizens than idle ones? Practical patriotism becomes second nature to children who learn early to regard the rights of others, to respect the laws, and to protect public property. The boy who raises wild fowl and liberates them or refrains from mutilating for purely selfish ends a fine tree is doing his share in the great work of conservation.