However, some of this earlier counsel, as well as somethat has since followed, failed in certain respects to ac-complish its aim for this reason alone: Without any doubt
at all, the writers knew their subject but they did notknow how to teach it. Only in a very small percentageof human beings does knowledge go hand in hand withthe ability to impart it. Knowledge is commendable:teaching an art acquired by all too few. Consequently,when we come upon a man possessed of knowledgegained from long and intensive experience plus the facultyfor teaching it as it should be taught, then we have a manwhose words should be heeded, and whose lessons can belearned.