HE CARUS MATHEMATICAL MONO- 
GRAPHS are an expression of the desire of 
Mrs. Mary Hegeler Carus, and of her son, Dr. 
Edward H. Carus, to contribute to the dissemination of 
mathematical knowledge by making accessible at 
nominal cost a series of expository presentations of 
the best thoughts and keenest researches in pure and 
applied mathematics. The publication of these mono- 
graphs was made possible by a notable gift to the 
Mathematical Association of America by Mrs. Carus 
as sole trustee of the Edward C. Hegeler Trust Fund. 
The expositions of mathematical subjects which the 
monographs will contain are to be set forth in a manner 
comprehensible not only to teachers and students 
specializing in mathematics, but also to scientific work- 
ers in other fields, and especially to the wide circle of 
thoughtful people who, having a moderate acquaintance 
with elementary mathematics, wish to extend their 
knowledge without prolonged and critical study of the 
mathematical journals and treatises. The scope of this 
series includes also historical and biographical mono- 
graphs. 
The following books in this series have been pub- 
lished to date: 
No. 1. Calculus of Variations, by PROFESSOR G. A. 
Briss. (First Impression in 1925, Second Impression 
in 1927.) 
No. 2. Analytic Functions of a Complex Variable, by 
Proressor D. R. Curtiss. (First Impression, 1926.) 
No. 3. Mathematical Statistics, by PROFESSOR HL 
Rietz. (First Impression, April, 1927.)