It is no common thing to find an artist who, even if he be willing to try, is capable of expressing his aims and ideals with any clearness and moderation. Some people will say that any such capacity is a flaw in the perfect artist, who should find his expression in line and colour, and leave the multitude to grope its way unaided towards comprehension. This attitude is a relic of the days when "l'art pour l'art" was the latest battle cry; when eccentricity of manner and irregularity of life were more important than any talent to the would-be artist; when every one except oneself was bourgeois. The last few years have in some measure removed this absurdity, by destroying the old convention that it was middle-class to be sane, and that between the artist and the outer-world yawned a gulf which few could cross. Modern artists are beginning to realize their social duties. They are the spiritual teachers of the world, and for their teaching to have weight, it must be comprehensible. Any attempt, therefore, to bring artist and public into sympathy, to enable the latter to understand the ideals of the former, should be thoroughly welcome; and such an attempt is this book of Kandinsky's.