ANYONE WHO HAS EVER TRIED TO PRESENT rather abstract scientific subject in a popular " manner knows the great difficulties of such attempt. Either he succeeds in being intelligible concealing the core of the problem and by offering to the reader only superficial aspects or vague allusions, thus deceiving the reader by arousing in him the deceptive illusion of comprehension; or else gives an expert account of the problem, but in such
fashion that the untrained reader is unable to follow the exposition and becomes discouraged from reading any further.