In this paper I argue that Resource and Environmental economists are doing a disproportionate level of nonmarket valuation, "demand" or benefit estimation research, relative to what one could loosely call "supply" or cost analysis. By nonmarket valuation I mean deriving willingness-to-pay (WTP) values for unpriced goods and services. By cost analysis I mean economically oriented trade-off analyses e.g. estimating potential opportunity costs of managing forests to provide these goods and services. The first part of the paper reviews the basis of my skepticism of nonmarket valuation. The second part of the paper identifies why I believe cost analysis is a challenge, particularly in the context of ecological sustainability, and provides some examples of such work.