For whatever reason, prices are down again. Amazon at $68.23. Barnes & Noble at $69.15. Book Depository at $68.22 with free shipping worldwide. And you can still get 20% off at the publisher with code LYON2017 (that's $64 or £44, plus shipping).
Still looking for more reviews on any site where you might have bought one, please.
Update: those discounts didn't last; but maybe they'll be back.