It's "Private Eye", as in "Peeper" (1930's slang for a P.I. [P.I.:the anagram for a Shamus {which is, by the way, 40's slang for P.I.} [I thought I said that!] {No, you explained what a Peeper is} (No, that was me) {Oh, right. Then what'd you do?} [I can't remember...] ([{Screw it!}]).I always thought it was "Private I," as in Private Investigator, not "Private Eye."