The open-economy dimension is central to the discussion of the trade-offs that monetary policy faces in an increasingly integrated world. I investigate the monetary policy transmission mechanism in a two-country workhorse New Keynesian model where policy is set according to Taylor (1993) rules. I find that a common monetary policy isolates the effects of trade openness on the cross-country dispersion, and that the establishment of a currency union as a means of deepening economic integration may lead to indeterminacy. I argue that the common (coordinated) monetary policy equilibrium is the relevant benchmark for policy analysis showing that in that case open economies tend to experience lower macro volatility, a flatter Phillips curve, and more accentuated trade-offs between inflation and slack. Moreover, I show that the trade elasticity often magnifies the effects of trade integration (globalization) beyond what conventional measures of trade openness would imply. I also discuss how other features such as the impact of a stronger anti-inflation bias, technological diffusion across countries, and the sensitivity of labor supply to real wages influence the quantitative effects of policy and openness in this context. Finally, I conclude that the theoretical predictions of the workhorse open-economy New Keynesian model are largely consistent with the stylized facts of the globalization era started in the 1960s and the Great Moderation period that followed.