"Supralapsarianism is the view that God, contemplating man as yet unfallen, chose some to receive eternal life and rejected all others. So a supralapsarian would say that the reprobate (non-elect) vessels of wrath fitted for destruction (Rom. 9:22) were first ordained to that role, and then the means by which they fell into sin was ordained. In other words, supralapsarianism suggests that God's decree of election logically preceded His decree to permit Adam's fall—so that their damnation is first of all an act of divine sovereignty, and only secondarily an act of divine justice." 
This view is most often contrasted with Infralapsarianism (also known sometimes as "sublapsarianism") which suggests that God's decree to permit the fall logically preceded His decree of election. So when God chose the elect and passed over the non-elect, He was contemplating them all as fallen creatures.
- Supralapsarianism: The Fall of Man Was Both Necessary and Wonderful, by Theodore Beza
- Notes on Supralapsarianism & Infralapsarianism, by Phil Johnson
- Infralapsarianism & Supralapsarianism, by Loraine Boettner
A blog on everything Supra by Scott Price
- Review of Edwin Chr. van Driel, Incarnation Anyway: Arguments for Supralapsarian Christology (Oxford: Oxford University Press, 2008), xi + 194 pp. $74.00