It is less improbable that the serious student has been choosing his books badly. He may do this in two ways--absolutely and relatively. Every reader of long standing has been through the singular experience of suddenly *seeing* a book with which his eyes have been familiar for years. He reads a book with a reputation and thinks: "Yes, this is a good book. This book gives me pleasure." And then after an interval, perhaps after half a lifetime, something mysterious happens to his mental sight. He picks up the book again, and sees a new and profound significance in every sentence, and he says: "I was perfectly blind to this book before." Yet he is no cleverer than he used to be. Only something has happened to him. Let a gold watch be discovered by a supposititious man who has never heard of watches. He has a sense of beauty. He admires the watch, and takes pleasure in it. He says: "This is a beautiful piece of bric-à-brac; I fully appreciate this delightful trinket." Then imagine his feelings when someone comes along with the key; imagine the light flooding his brain. Similar incidents occur in the eventful life of the constant reader. He has no key, and never suspects that there exists such a thing as a key. That is what I call a choice absolutely bad. The choice is relatively bad when, spreading over a number of books, it pursues no order, and thus results in a muddle of faint impressions each blurring the rest. Books must be allowed to help one another; they must be skilfully called in to each other's aid. And that this may be accomplished some guiding principle is necessary. "And what," you demand, "should that guiding principle be?" How do I know? Nobody, fortunately, can make your principles for you. You have to make them for yourself. But I will venture upon this general observation: that in the mental world what counts is not numbers but co-ordination. As regards facts and ideas, the great mistake made by the average well-intentioned reader is that he is content with the names of things instead of occupying himself with the causes of things. He seeks answers to the question What? instead of to the question Why? He studies history, and never guesses that all history is caused by the facts of geography. He is a botanical expert, and can take you to where the *Sibthorpia europæa* grows, and never troubles to wonder what the earth would be without its cloak of plants. He wanders forth of starlit evenings and will name you with unction all the constellations from Andromeda to the Scorpion; but if you ask him why Venus can never be seen at midnight, he will tell you that he has not bothered with the scientific details. He has not learned that names are nothing, and the satisfaction of the lust of the eye a trifle compared to the imaginative vision of which scientific "details" are the indispensable basis.