It is impossible to compare Frege's Foundations of Arithmetic! with the writings on the philosophy of mathematics of Frege's predecessors-even with such great philosophers as Kant-without concluding that Frege's work represents an enormous advance in clarity and rigour. It is also hard to avoid the conclusion that Frege's analysis increases our understanding of the elementary ideas of arithmetic and that there are fundamental philosophical points that his predecessors grasped very dimly, if at all, which Frege is clear about.