But simply to take regular exercise in composition is not quite enough. Of it would come the shadow but not the substance. To progress as a writer, one must become a student of the best things which have been written by men who understand their craft. A military officer can do that without going beyond the field of military studies, if that should be his disposition, such is the richness and variation of available works in this realm of literature. The purpose at hand is not only to seek great ideas for their own sake but to make careful note of the manner in which they are expressed. So doing, one unconsciously invigorates his own powers and adopts techniques which the masters have used to great advantage. To paraphrase what a distinguished journalist once said on this subject in a speech to young writers: "For an officer it is in the first place a shame to be ignorant--ignorant, as not a few are, of history and geography: and in the second place, it is a pity that any officer should lack a vigor in writing which can be produced through imitation of vigorous writers." As to what is best worth seeking, a man can not go wrong by "falling in love" with the works of a relatively limited number of authors who kindle him personally. It is all right to widen the field occasionally, for diversion, for contrast, for sharpening style, and for balancing of ideas, but strength comes of finding a main line and holding to it. No man can read a book with sympathetic understanding without taking from it something that makes him more complex and more potent. The main test is in this: if you read a book and feel stirred by it, even though alternately you strongly agree with certain of its passages and warmly contend against others, something new has been added. The writer is making you see things. Your own powers of observation are being made more acute. All good writers are in a sense hitch-hikers. While going along for the ride, and enjoying the essence of some highly developed mind, they are not loath to study the technique by which some other man develops his driving power, and to make note of his strong words and best phrases for possible future use. It is a good habit to underscore passages in books which have contributed something vital to one's own thought--always provided that the books have not been borrowed.