This is the single best introduction to cost-benefit analysis available. I teach a master's level-upper division course in cost-benefit analysis at the University of California, San Diego, and have looked at many books. I always come back to this one. Because it is unfortunately out of print, I have to place it on reserves rather than having the students purchase it. The book contains a surprising amount of information and very mature insights into the philosophical and ethical basis of applied welfare economcis and cost-benefit analysis. Yet the book does not bog down in unneccessary detail or technicalities. The book is unfortunately too limited in its scope and could be updated and expanded. It should also spend a chapter or two on project evaluation in less developed countries. I have to use Kohli's book, Economic Analysis of Investment Projects, for this purpose. There are other books which contain more detail but these require a more sophisticated knowledge of microeconomics and especially applied welfare economics. An expanded version of the book could also profit from more practical information on "how to do" cost-benefit analysis, such as along the lines of Sassone and Schaefer, Cost-Benefit Analysis. The book is well written.

A super helpful book for non-econ, calculus-literate students of environmental science. For environmental econ students, here's an excellence reference book that explains the basic models more thoroughly than most other environmental econ books. Also includes a reasonable amount of bibliographical information to start off research in the discipline.