Concentration is a state secured by the mental activity called attention. To understand concentration we must first consider the more fundamental facts of attention. <p 109> In the evolution of the human race certain things have been so important for the individual and the race that responses towards them have become instinctive. They appeal to every individual and attract his attention without fail. Thus moving objects, loud sounds, sudden contrasts, and the like, were ordinarily portents of evil to primitive man, and his attention was drawn to them irresistibly. Even for us to pay attention to such objects requires no intention and no effort. Hence it is spoken of as _*passive_ or _*involuntary attention_. The attention of animals and of children is practically confined to this passive form, while adults are by no means free from it. For instance, ideas and things to which I have no intention of turning my mind attract me. Ripe fruit, gesticulating men, beautiful women, approaching holidays, and scores of other things simply pop up in my mind and enthrall my attention. My mind may be so concentrated upon these things that I become oblivious to pressing responsibilities. In some <p 110> instances the concentration may be but momentary; in others there may result a day dream, a building of air castles, which lasts for a long time and recurs with distressing frequency. _Such attention is action in the line of least resistance. Though it may suffice for the acts of animals and children it is sadly deficient for our complex business life_. Even here, however, it is easy to relapse to the lower plane of activity and to respond to the appeal of the crier in the street, the inconvenience of the heat, the news of the ball game, or a pleasing reverie, or even to fall into a state of mental apathy. The warfare against these distractions is never wholly won. Banishing these allurements results in the concentration so essential for successfully handling business problems. The strain is not so much in solving the problems as in retaining the concentration of the mind. When an effort of will enables us to overcome these distractions and apply our minds to the subject in hand, the strain soon repeats itself. <p 111> It frequently happens that this struggle is continuous--particularly when the distractions are unusual or our physical condition is below the normal. No effort of the will is able to hold our minds down to work for any length of time unless the task develops interest in itself. This attention with effort is known as _*voluntary attention_. It is the most exhausting act which any individual can perform. Strength of will consists in the power to resist distractions and to hold the mind down to even the most uninteresting occupations. _Fortunately for human achievement, acts which in the beginning require voluntary effort may later result without effort_.