The reader who desires to study further on the sub­ject of thinking will find a wide field before him—but he will have to search in cos­mo­pol­i­tan quarters. While much has been written on thinking, it has been in an incidental manner, and has found its way into books written mainly to il­lum­i­nate other subjects. Among the few books or essays devoted exclusively or mainly to thinking may be mentioned:—John Locke, The Conduct of the Under­stand­ing; Isaac Watts, The Improvement of the Mind; Arnold Bennett, Mental Efficiency; T. Sharper Knowlson, The Art of Thinking; Arthur Schopenhauer, On Thinking for Oneself, in his Essays. The last is especially recommended. It is only about a dozen pages long, and is the most stimulating essay written on the subject. This, together with John Locke’s Conduct (which, by the way, is also fairly short) may be con­si­dered the two “classics” in the meager literature on thinking.

There is an extensive literature on the psychology of reasoning, on the “positive” science of thinking. The best single work on this subject is John Dewey’s How We Think. William James’ chapter on Reasoning in his Principles of Psychology might also be consulted with profit. S. S. Colvin’s, The Learning Process con­tains some in­teresting chap­ters bearing on thought.

On method, the amount of literature is even more imposing than that on the psychology of reasoning. Probably the most thorough book is Stanley Jevon’s The Principles of Science, though this, consisting of two volumes, will require quite some ambition to attack. A good recent short work is J. A. Thomson, Introduction to Science. Herbert Spencer’s short essay, An Element in Method, in his Various Fragments might also be mentioned. Of those works treating method mainly from a corrective standpoint, I have already mentioned Jevon’s Elementary Lessons in Logic. The authoritative and most comprehensive book on logic is still John Stuart Mill’s great tome. Of course this list of books on method, as well as that on the psychology of reasoning, cannot pretend to be more than merely suggestive. If the reader desires an extensive bibliography in either of these subjects he will probably find it in one of the books mentioned.

On doubt and belief, William Clifford, The Ethics of Belief, and William James, The Will to Believe, might be read. The viewpoints of the two essays are in almost direct contradiction.

On reading, Alexander Bain’s The Art of Study, in his Practical Essays, will be found useful. Bacon’s essay On Studies, which is not more than a couple pages long, contains more con­cen­trated wisdom on the subject than is to be found anywhere.

On subjects most worth thinking about, the reader cannot do better than read Herbert Spencer’s essay What Knowledge is of Most Worth? in his Education. As to books most worth reading, consult the lists of John Morley, Sir John Lubbock, and Frederic Harrison; Sonnenschein’s Best Books (in two volumes); Baldwin’s The Book Lover; Dr. Eliot’s Five Foot Shelf and Frank Parson’s The World’s Best Books, previously referred to.

On the art of living—the art of planning time so as to have room for thinking, as well as valuable hints as to how that thinking is to be carried out—consult Arnold Bennett, How to Live on Twenty-four Hours a Day, and E. H. Griggs, The Use of the Margin (both very, very small books).

Finally, there is much useful material, as well as incalculable inspiration, to be obtained from the in­tel­lec­tual and literary biographies of great thinkers. Especially is this true of auto­bio­graphy. Among others may be mentioned the auto­bio­graph­ies of John Stuart Mill and Herbert Spencer, and an auto­bio­graph­i­cal frag­ment by Charles Darwin.