Nova War has, according to my publisher's, been selling really well - this is as far as I know the main reason it keeps showing up on Amazon as 'currently out of stock'. It's not, to my knowledge, so presumably as soon as it arrives it gets mailed out again. I did start to get slightly worried, however, when I noticed one or two tweets by random people saying they were having trouble tracking down copies. I also know that acquaintances and friends would tell me in the past that when they went looking for my new books in physical bookshops, they had trouble finding them (mind you, this was usually specifically in terms of trying to find stuff in Borders, and obviously that's not going to be a problem for much longer). Has anyone reading this blog had trouble tracking copies down?
Edit: Got an email from Tor that it's back in stock in the bookshops, and shows up as in stock on Amazon. For now, anyway.