I wish you to feel that this sort of study has no limits. Its interest will last you, as long as you live. At the same time my aim is to help you to enter upon the study. And at the start everything should be made as simple as possible. So, although motives and points of view are infinite in variety, let us see if we cannot find some simple clue to the study of them. I think it may be found in dividing all artists into two big groups. On the one side, those who are inclined to represent the world as they see it to be; on the other side, those who represent things according to their own ideas. It is the great division between the _naturalistic_ or _realistic_ and the _idealistic_ motive and point of view. Some artists are naturalists, or realists; others are idealists; a great many are a mingling of the two.