This choropleth map displays a "Literary Population Score" for selected countries, using a blue sequential color scale to represent values from 0 to 100. It loads world geometry from a TopoJSON file via `d3.json` and converts it to GeoJSON features using topojson, then draws the countries with `d3.geoPath` and a Mercator projection. Country fills are determined by looking up three-digit numeric ISO codes in a `Map`, with tooltips showing names and scores. A vertical legend uses `d3.scaleSequential` and `d3.interpolateBlues` to explain the color mapping.