Taste is so free and so subjective, so largely a matter of personal feeling, that any selection or limitation of attractive objects would be met by plausible objection. Every honest and unprejudiced investigator must, however, admit nowadays that his individual taste may be informed and purified, and that he is under obligations to be ever ready to explain and to justify it. The day for the mere proclaiming of preference has passed. The proclamation must be accompanied by explanations which will satisfy others, if they do not convince them, and which will be clear to one’s own understanding. The authoritative explanation, “I like this, I dislike that,” will no more pass current nor carry weight. Science has sufficiently studied the sentiments and emotions to know that they, too, are subject to laws which must be acknowledged and obeyed. Excitations for which there is no reasonable accounting, no justifiable source, must be relegated to the domain of folly. The reason for everything that appertains to thought and emotion, if not apparent, must be exposed and presented. Artists must explain their works to vulgar understanding. Writers must make their criticisms plain to the humble intellect. The age in which we live takes nothing for granted, accepts no man’s _ipse dixit_, hates shams, is intolerant of secrecy, hypocrisy, and fraud. I propose in this article, by contrasting good and bad examples, to put before readers a few of the simplest elements of decoration. You can hardly fail to note the differences, and when once the eye has acquired the habit of discriminating there is no reason why there should not follow a growth in perception which will result in delightful and augmenting artistic enjoyment. No attempt is to be made to develop a system, nor, of course, to cover the whole ground of the subject. The object is simply to start perceptions in the right direction. Almost all the ideas and the illustrations of this article are taken from a little work by Henri Mayeux, called _La Composition Décorative_. Henri Mayeux is Professor of Decorative Art in the École des Beaux-Arts in Paris. His work is one of the series of the _Bibliothèque de l’Enseignement des Beaux-Arts_, a series which should be among the very first works to be found in the library of every student of art. [Illustration: FIG. 1.]