I’ve just heard from IVP that the pre-release discount of 50% is still available until Dec 6.
(Dec 6 was the official launch date, but the book was released early.)
So if you are intending to purchase in bulk, now is the time to act.
I’m assuming the discounts on What Jesus Started and Movements that Change the World also remain until Dec 6.
For all those waiting for the electronic version (Kindle & IVP pdf), it is coming soon, but I don’t know the exact date.