A paleolithic diet is found in The Primal Blueprint, written by Mark Sisson, a former world-class endurance athlete with a degree in biology. The Primal Blueprint is based on the concept of eating foods that were available to our Paleolithic ancestors because this is the diet that our genes are designed for. It also involves addressing other lifestyle factors that have an important influence on our health and our ability to maintain an optimal physique. Source: http://www.everydiet.org/diet/primal-blueprint-paleolithic-diet
The main variation to Paleo appears to be the inclusion of lactose-free dairy.
Useful primal sites: