e93s are definitely my favorite set as well. To answer some questions - collins, IMO, is one of the worst looking cards in the set. Its also not Eddie Collins that is pictured - I believe the consensus is that its Jimmy Collins (at least its still a HOFer). As for the blank backs, I dont believe they are considered "proofs." Rather, they seem to have all been hand cut from sheets that did not have printing done on the reverse - I think many dont consider them proofs because there is no evidence of alignment marks on the cards. Maybe the shees were printers scraps - I dont really know. I have a couple and, like Jim B. tend to think they are rarer than what the common belief may be. I know he's done it before, but hopefully Jim B. can expand on this. While Jim has the nicest high grade set of e93s Ive ever seen, I like to think Ive got some of the nicest low to mid grade e93s out there (though Ive up graded many cards in my set, some of these will probably never be upgraded despite the lower grades). My apologies to anyone who's seen enough of these: And a blank back for good measure: