At the beginning of the present century, the literature on financial integration focused on the benefits of increased integration. In particular, the literature emphasized that a well-integrated financial system allows economic agents to engage in risk sharing while enhancing the smooth transmission of monetary policy. However, the international financial crisis of 2007-08 and the euro area sovereign debt crisis of 2009-15, brought to the fore the flip side of increased financial integration – namely, that higher financial integration among national jurisdictions creates the potential for destabilizing cross-country spillovers of capital flows. The papers in this Special Issue address financial system vulnerabilities in the aftermath of the 2007-08 financial crisis and the 2009-15 euro area crisis. In particular, the papers assess (1) vulnerabilities arising from such factors as the liberalization of financial systems, cross-country contagion, and climate change, and (2) policy responses, including macroprudential supervision and quantitative easing, to financial instabilities.