This exquisitely designed, printed, boxed and bound book was never for sale, it came as a gift from BMW AG to the original purchaser of each Z8.
If you bought your car second hand and it didn't come with the book it may well be because the original owner never got it, as surprisingly few people within BMW and their sales team are even aware of it, or that he chose to keep it, so sadly there isn't much you can do about it. I know many have tried, and none have succeeded. I tried to match my old Euro Z8 with it's book, but despite two years of trying was never able to.
In the end I bought this one below from EBay. The seller wouldn't let it go for less than $750, it never reached it's reserve in that sale, he emailed me as highest bidder, and named his price! So if you want one, keep an eye on EBay and be prepared to pay for it. This book was for a European spec Stratus car made in final year of production.
As a collector of rare photographic books I think it is actually a reasonable price for this unique piece. It is one of the very most beautifully made books in my very considerable book collection. Every part of it is sensational, and I expect it to become as collectable as the car itself. I'm confident if you have to buy yours it will a great investment, just like the car itself.
As of August 2016 the entire stock of books that BMW NA had have now been allocated, so pretty much the only way to now find a book is on eBay.