I think I may have understood it now all of a sudden… basically says something along the lines of “This time it’s an unusual three-part series”. Gōshō put the kanji for first/before (前), second/middle (中), and third/latter (後) all together before the kanji for volume/chapter (編) to form a slang word meaning it’s divided in first, second, and third chapter. Basically it’s a single compound word that doesn’t turn up anything in dictionaries but has that meaning, I think. I’ll go put that on the wiki, anyway, if anyone has something against it you can bring it up to Fujiwara or something.