What is the difference between raisins, currants and sultanas?

Ever wondered what raisins, currants and sultanas were before they were dried out? The answer is simple:

Raisins     = dried grapes Currants  = dried grapes Sultanas  = dried grapes

Of course it isn’t quite as simple as that or raisins, currants and sultanas would all look and taste the same. The differences are primarily due [...]