Throughout Europe, butterflies are disappearing at an alarming rate, possibly faster than any other form of wildlife. Moreover, it seems that their declines are set to accelerate over the next few decades because most species cannot withstand the rapidity of the changes now affecting Europe's countryside. Their future is inextricably linked with man's use of the land, but we are only just beginning to understand the full extent of their human dependence and its implications for their chances of survival.