I've just spotted this on Amazon, so I know as much as you about the forthcoming Mods & Rockers: The Origins of a British Scene by Gareth Brown (who you may recall, wrote the Scooter Boys book).
Published by Independent Music Press on 23rd September, it's a 128-page book with 'over 50 rare b/w photos' and according to the write-up: 'This book explains the genesis of both movements right through from their conception to the cell splitting that separated them. It will closely study their development, and most importantly, highlight their enduring legacies on the popular culture scene of today.'
No sign of a review copy, so you'll have to take a chance on it. However, Amazon is doing pre-orders, heavily marking it down to just £7.79.