This study provides a view of the inflation process that is complementary to the onecaptured in standard models，such as those based on the Phillips curve. ltcharacterises the process as two regimes - a low- and a high-inflation regime - withself-reinforcing transitions from the low- to the high-inflation one. The studydocuments the stylised facts describing the two regimes and the transitions betweenthem based on disaggregated price dynamics and the joint behaviour of wages andprices. Two implications for monetary policy stand out.First, the desirability ofconducting monetary policy in a flexible manner in a low-inflation regime, toleratingmoderate, even if persistent, deviations from narrowly defined targets. Second, theimportance of being pre-emptive when the risk of a transition to the high-inflationregime increases,even though assessing this transition in real time remainschallenging.