I recently read a book by Bob Friedhoffer called Magic and Perception and in this books he includes a detailed explanation of Card Warp. In his book he calls it The Inside Out Card Warp and his introduction to the effect reads:

"The idea for this trick originated with the magician Jeff Busby. It fools the audience with the help of a single rip in a playing card."

I wasn't aware that this effect was originated by Jeff Busby and was hoping to find out more about the history of this effect.

jeff

Into the Fourth Dimension - google from there

Multi phase routine where the card also gets ripped in half then restored at the end. The part we call card warp was (best I recall) the first magical effect in that routine - then came the tearing and covering the tear with take and then a restore.

As I recall, the card was folded and held with half in view so it looked, say, face down. The folded card was then spun end-for-end (in a similar way that you would with a color changing knife) and it was now face up. Walton credits Busby in his instructions (copyright Davenports) for this initial inspiration.

Peter