Fan of The Baby-sitters Club?

Then don't miss this: The Definitive Ranking Of All 131 Baby-Sitter’s Club Cover Outfits.

Can someone please explain to me why there's not an apostrophe (preferably plural possessive, thanks Speak 'N' Spell!) in the title of the series? I've always wondered.

ETA: APPARENTLY, I AM NOT ALONE IN BEING CONFUSED.

ETA REDUX: Thanks to a friend on Facebook, here's the relevant bit from the first book in the series:

Janine and the apostrophe

Poor old Janine. I always did feel for her.

Books -- JuvenileLeila RoyComment