Four major central banks have adopted new approaches to policy rate forward guidance with the aim of enhancing the effectiveness of monetary policy at the zero lower bound. In this special feature, we examine these approaches and assess their impact. So far, the forward guidance appears to have led to lower volatility of near-term expectations of the future path of policy rates, but the effects on the level of interest rate expectations and on the responsiveness of financial markets to news are less clear. At the same time, the forward guidance raises a number of significant challenges. How they are managed will ultimately determine the enduring value of this communication tool.