"I have tried to say to students of mathematics that they should read the classics and beware of secondary sources. This is a point which Eric Temple Bell makes repeatedly... in '... that the men of whom he writes learned their mathematics not by studying in school or by reading textbooks, but by going straight to the sources and reading the best works of the masters who preceded them. It is a point which in most fields of scholarship at most times in history would have gone without saying. ...The purpose of a secondary source is to make the primary sources accessible to you."