@Gary James has posted on here before that, back in the mid-1990s, he was looking for a publisher for what was effectively a proposed City version of Fever Pitch, and received an offer conditional on him focusing the text on the hapless Blues forever flailing in the shadow of their mighty red neighbours. He refused but Shindler didn't, the resulting book being published a year or two later.
I believe that Shindler's book shifted well over 100,000 copies, making it comfortably the biggest selling City book (if you can class it as that) of the lot.