(1) _General knowledge._ Since the purpose of this study of the pupil is to afford a general knowledge of life, four preliminary statements will suffice in this connection. (a) Life is constantly changing. This change is evident in growth or increase in size and development or increase in power. It occurs not only in the body but the soul as well, or that part of life which is not physical, and is a result of nourishing food and proper exercise. The Sunday-school has recognized this fact of change by its division of the life of the pupil into six periods, Beginners, Primary, Junior, Intermediate, Senior, and Adult. These periods mark different stages in development. (b) Each period has certain predominant characteristics and out of these characteristics arise definite opportunities and needs. To meet these opportunities and needs is the goal of work for each period. The final goal of developed Christian character can be attained only through reaching the goal of each period. (c) Development is gradual, constant and progressive. The soul comes into the world containing infinite but undeveloped possibilities. The unfolding is gradual and constant as the possibilities are called out by the needs of the life. There is also an order in unfolding. The soul develops power for simple mental processes first and for the complex later: interest in self first and in others later; consciousness of the natural first, the spiritual later. The teacher who knows God's order, obeys his laws and waits his time is the teacher whose seed sowing is reaped in the hundredfold harvest. (d) It is impossible to ignore the physical and mental side of the pupil and be successful in spiritual work with him. The lesson cannot reach the soul save by way of physical senses and a physical brain and mental processes identical with those necessary in apprehending a history lesson. The Holy Spirit applies the truth to the life but he has only so much to apply as has been received into the mind. Therefore pure air and bodily comfort, acute senses and obedience to the laws of the mind are as surely linked with spiritual work as prayer. (2) _Specific knowledge._ Though all lives possess the same general characteristics and are under the same general laws, no two lives are identical. Some unfold more rapidly than others, some have larger capacity and more latent possibilities than others and all are in differing circumstances. It is this variation that makes individuality, and the more perfect the adaptation of the teacher's work to the individual the greater the teacher's success.