The boys at the Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois have constructed a complex system of analysis to determine the greatest tennis player of all time. If you are really into this stuff, you'll love it, but it's going to be too technical for about 75% of this forum: http://www.plosone.org/article/info:doi/10.1371/journal.pone.0017249 "In our top 10 list, there are 9 players having been number one in the ATP ranking. Our ranking technique identifies _____________ as the best player of the history of tennis. This could be a posteriori justified by the extremely long and successful career of this player. Among all top players in the history of tennis.... Prestige score is strongly correlated with the number of victories, but important differences are evident when the two techniques are compared....."