In early days much of the advance in learning had to be reasoned out and then verified, if possible, by experiments. Now we reverse the process. Our scientists experiment first by observing phenomena under all sorts of conditions and then later try to reason to a satisfactory explanation which, even with all our learning, cannot always be found. In fact, the underlying explanation of many of the commonest things in life escape us. For example, we do not know a great deal more than the ancients about the ultimate constituents of matter, the nature of light or how our senses really work. Alhazen did valuable work himself but was far more important as the inspiration for study in optics for the greatest scientist of the Middle Ages, the first experimental scientist and one of the greatest Englishmen of all time, Roger Bacon. _II_ FRIAR BACON’S MAGIC _Roger Bacon, English monk of the 13th Century, studies the ancients--and the Greeks--and inaugurates the scientific study of magic shadows and devices for creating them._ Roger Bacon made a great contribution to human knowledge, especially in scientific matters. Yet this great philosopher and scientist was generally regarded as “Friar Bacon,” a mad monk who played with magic and dealt with the powers of darkness. This myth persisted even though Bacon’s contemporaries had bestowed upon him the title of “Doctor Mirabilis.” Studies made in the 19th century and the first part of this century have tended to confirm him in his proper high place in history. Roger Bacon was born at Ilchester in Somersetshire, England, about 1214, the year before the Magna Charta was signed. In those days serious education began early. When Bacon was 12 or 13 he was sent to Oxford. Later on he continued his studies at Paris. In his youth Bacon’s family gave him the considerable sums he needed for his education. After completing his studies, Bacon was a professor at Oxford and then entered the Franciscan Order. As a monk he found the pursuit of learning somewhat more difficult even though the libraries of the religious orders were the best of the period and most of the learned men were ecclesiastics. After having taken a vow of poverty Bacon had difficulty in obtaining from some of his superiors money to buy pens and pay copyists. Certain authorities did not look with complete satisfaction on his experimental science investigations and they liked even less his barbed comments on other philosophers of the day.