The design of a book is the pattern of a reality controlled and shaped by the mind of the writer. This is completely understood about poetry or fiction, but it is too seldom realized about books of fact. And yet the impulse which drives a man to poetry will send another man into the tide pools and force him to try to report what he finds there.... It would be good to know the impulse truly, not to be confused by the 'services to science' platitudes or the other little mazes into which we entice our minds so that they will not know what we are doing.