Just what subject you make your specialty I am not at present concerned. It may be aeronautics, astronomy, banking, Greek history, differential calculus, social psychology, electricity, music, philosophy of law, submarines, soap manufacture, religion, metaphysics, sun-motors, education, literary style or the moon. But whatever it is, it ought to be a subject in which you are interested for its own sake—which most frequently means one which you do not make your vocation. If you get tired of it, drop it and take up something in which you are interested. Your thinking and study should be pursued as a pleasure—not as a duty. If your subject is a narrow one, if let us say it is merely a branch of what is generally considered a science, you should first get a clear idea of the broad outlines of the science before taking the specialty up. Should you, for instance, select the tariff, begin your study by using as your main text a book on general economics. Even if you make your specialty an entire science you will derive great help by reading in other sciences. In ethics, for instance, a knowledge of psychology, biology and sociology will prove of surprising value. This means that for the sake of knowing the specialty itself, if for nothing else, you should not pursue it exclusively. If ever you find yourself in danger of doing this it would be well to lay down a rule that every third or fourth book you read must be one which does not deal with the subject you have chosen as your own. VIII WRITING ONE’S THOUGHTS Reading maketh a full man, conference a ready man, and writing an exact man.—BACON. Any attempt to formulate a science or art of thinking would not be complete without at least some discussion of writing. Indeed writing is so closely bound up with thinking that I have been compelled to refer to it several times in the discussion of thought and reading. I have already spoken of writing as an aid to concentration. I was wont to depreciate it on account of its slowness. But this is practically its only fault. Thoughts come to us when writing which we get in no other way. One is often surprised, when reading something one has written at a previous time, at some of the remarks made. We seem to have temporarily grown wiser than ourselves. But the great advantage of writing is that it preserves thought. What printing has done for humanity in preserving the knowledge of the ages, writing will do for the individual in preserving his own reflections.