Highest and Best Use is often identified as the key concept supporting real estate use and value decisions. However, at best the concept has received ambiguous if not conflicting consideration as to its relevance in the literature of economics, finance, real estate, appraisal and other areas of study concerned with land use decisions and valuation. This paper addresses this ambiguity and identifies the theoretical premises of Highest and Best Use as employed in the various land use disciplines. The theoretical foundations as they have synthesized form the basis of a formal constrained optimization model for land use decisions. The model's logic identifies the need to include the cost of capital and location along with the physical, legal, infrastructure and market parameters discussed in the bulk of the economic and appraisal literature (including courses and professional practice). The financial and locational variables are needed in order to advance the use paradigm to fit the current context of problems facing real estate decisionmakers.