Although the main text of this paper was a chapter in Sociophysics (1993 & 2005) it was edited and updated to fit this research proposal during the Ides of March, 2016. ----------------------------------------- Although there are many international statistics on economic production flows (e.g. GNP), there are no comparative data on social material capital. Such data has never been collated and compared, let alone analyzed and synthesized. This omission leaves a significant lacuna in understanding the impact of the cultural World socio-system, distinct from but built upon a surface of the natural Earth planetary ecosystem. This article presents a project to correct that problematic situation by measuring the physical aspects of the Global Society, expressed as the Weight of World (WoW). By discovering certain fundamental traits characterizing social systems, it will relate their economic, political and cultural sectors, as well as their natural environment, in synchronic comparison and diachronic history. Eventually, new information will be given primarily by means of a Gross National Mass (GNM) for each city, country, and region of the world. The data thereby accumulated, when summarized and analyzed will present a more complete picture of the world, thus enabling social scientists and decision-makers to improve their knowledge of the international system and act accordingly. To measure the GNM, the sociophysics paradigm will submit its conceptual framework and mathematical formulae. This statistical quantitative methodology will construct and apply a Socio-Physical-Index (SPI) as central measure of each country’s GNM, compared to its GNP. SPI will reflect the sum of the mass of humans, as well as their possessions and creations, by estimating and quantifying existing data from various sources. The end product could be a published as an annual report on the state of the world, collating, tabulating and commenting on the detailed SPI of each country, as well as the correlation it has on important economic, ecological and political indicators.