The lecture was in two parts. The first part outlined the changes in methods of measurement and the range of thermodynamic-property determinations made at Bartlesville since the laboratory was initiated by Hugh M. Huffman in 1943. Emphasis was placed on those changes made in the last decade to aid the laboratory in maintaining its position at the leading-edge of research, while remaining relevant to its product users, the process-design industry. As the twenty-first century draws near, the process-design engineer has added burdens. In the past, the process-design engineer’s goal was the design of a safe process, which made the product at an economic cost. Today’s environmental regulations which restrict emissions, waste production, etc., are added burdens which need careful attention if maintenance of the economic advantage is to be accomplished. In the second part of the lecture, emphasis was placed on the need for accurate and precise measurements as the basis for new intelligence systems designed to aid the process-design engineer of the twenty-first century. Three case studies were given where calorimetric and statistical-mechanical calculations were used in conjunction to delineate the limitations of the measurements. Topics discussed included the limitations of corresponding states, the virial equation, and statistical-mechanical calculations. Using NIPER DOE Fossil Energy Topical Reports, three examples of the application of the thermochemical and thermophysical property measurements to current problems within the refining industry were discussed. The examples discussed were (i), the level of aromatics in diesel fuel; (ii), the relative reactivity of aromatic nitrogen-containing compounds in hydrodenitrogenation (HDN); and (iii), "hydrogen shuttling" in coal liquefaction and heavy-petroleum visbreaking.