PREFACE 
vii 
theory of numbers; but an elementary exposition is available 
in the author’s recent book, On Invariants and the Theory of 
Numbers, published, together with Osgood’s lectures on func 
tions of several complex variables, by the American Mathematical 
Society, as The Madison Colloquium. 
In addition to numerous illustrative examples, there are four 
teen sets of exercises which were carefully selected on the basis 
of experience with classes in this subject. 
The author is indebted to Professor H. S. White for suggest 
ing certain additions to the initial list of topics and for reading 
the proofs of Part I. 
Chicago, May, 1914.