If the layman's interest in art is more than the casual touch-and-go of a picture here, a concert there, and an entertaining book of an evening, he is confronted with the important matter of the study of art as it manifests itself through the ages and in diverse lands. It is not a question of practicing an art himself, for technical skill lies outside his province. The study of art in the sense proposed has to do with the consideration of an individual work in its relation to all the factors that have entered into its production. The work of an artist is profoundly influenced by the national ideals and way of life of his race and of his age. The art of Catholic Italy is ecclesiastical; the art of the Protestant North is domestic and individual. The actual form an artist's work assumes is modified by the resources at his disposal,--resources both of material and of technical methods. Raphael may have no more to say than Giotto had, but he is able to express himself in a fuller and more finished way, because in his time the language of painting had become richer and more varied and the rhetoric of it had been carried to a farther point of development. Finally, as all art is in essence the expression of personality, a single work is to be understood in its widest intention and scope by reference to the total personality of the individual artist as manifested in his work collectively, and to be interpreted by the appreciator through his knowledge of the artist's experience of life. In order to wrest its fullest expressiveness from a work of art it is necessary as far as possible to regard the work from the artist's own point of view. We must try to see with his eyes and to feel with him what he was working for. To this end we must reconstruct imaginatively on a basis of the facts the conditions in which he lived and wrought. The difference between Giotto and Raphael is a difference not of individuality only. Each gives expression to the ideals and ways of thought of his age. Each is a creative mind, but each bases his performance upon what has gone before, and the form of their work is conditioned by the resources each had at his disposal. To discover the artist's purpose more completely than he was able to realize it for himself in the single work,--that is the aim and function of the historical study of art. A brief review of the achievement of Giotto and of Raphael may serve to illustrate concretely the application of the principle and to fix its value to appreciation.