PREFACE 
THIS book is an attempt to put on a rational foundation 
the concepts and fundamental theorems of capital and 
income. It therefore forms a sort of philosophy of eco- 
nomic accounting, and, it is hoped, may supply a link long 
missing between the ideas and usages underlying prac- 
tical business transactions and the theories of abstract 
economics. To some readers it may seem that certain 
elementary topics have been treated at undue length ; but, 
as experience shows that economic structures built on 
hasty and inadequate generalizations inevitably collapse, 
it seems hardly possible to take too much pains in making 
the foundations secure. On the other hand, topics which 
are in their nature technical or which digress from the 
main theme — and in particular mathematical formule — 
have been relegated to appendices. 
Many of the theses maintained will undoubtedly fail 
to command assent on a first reading, for in any orderly 
presentation of a subject it is impossible to forestall all 
objections as they occur. The aim has been to pre- 
serve a definite sequence by which each step prepares 
the way for those which follow; but this plan has ne- 
cessitated the postponement of some topics beyond the 
point at which a consciousness of their difficulties 
might begin to trouble the reader. He is therefore 
asked to stay judgment until he has finished the work, 
and, if necessary, to reread those parts in which his diffi- 
culties were first encountered. This suggestion is espe- 
cially urged in regard to the treatment of income, the 
concept of which forms the central theme of the book. 
Many of the friendly critics to whom the manuscript has 
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