In the last few years, there has developed a large literature, sometimes referred to as the new quot;public finance,quot; providing a quantitative analysis of a number of traditional problems within the field. This paper is concerned with surveying, or interpreting, what can be learned from this literature; and our belief is that it has taught us a great deal. We concern ourselves here not so much with the derivation of precise formulae, e.g. for optimal tax rates, but with the more general lessons which have emerged