The Belt and Road initiative is perhaps both the most significant and least well understood foreign policy initiative of the 21st century. This talk will explore the logic behind the BRI and its expanding scope — now encompassing more than half the world’s population and GDP. With the BRI’s focus on infrastructure investment, the priorities for investment will be explored. Financing these investments has raised concerns about debt sustainability in recipient countries, but these appear to be exaggerated. But there are constraints in China’s ability to continue to finance the bulk of BRI investments, which call for greater participation by other countries and international financial institutions.