Kasparov vs. Karpov 1975-1985

The next tome in Kasparov's series on the World Championship has been announced for August. Since I first heard it about it from Newinchess.com, I'll reference their page: Kasparov vs Karpov 1975-1985.

The full title is Garry Kasparov on Modern Chess, Part 2: Kasparov vs Karpov 1975-1985. It's the sequel to Garry Kasparov on Modern Chess, Part 1: Revolution in the 70s, a book published in March 2007, that didn't receive much attention. Amazon.com lists 'K-K 1975-85' for $29.70; Amazon.co.uk lists it for £28.50. At current exchange rates, that's twice the price. Here is the 'Amazon.com Sales Rank (in Books)' for the series:

• My Great Predecessors, Part 1 (August 2003); #282,544
  
• My Great Predecessors, Part 2 (January 2004); #286,583
  
• My Great Predecessors, Part 3 (November 2004); #261,378
  
• My Great Predecessors, Part 4 (Fischer, January 2005); #40,735
  
• My Great Predecessors, Part 5 (March 2006); #183,014
  
• Part 1: Revolution in the 70's (March 2007); #264,777

Even Garry will admit that Fischer sells. I already have Kasparov's books on the 1985 (KK2), 1986 (KK3), and 1990 (KK5) matches. How much new material is in the latest series?