Microsoft Dynamics AX 2012 Security How-To - Available now
I read it, but find it a bit thin. There's not really any new information that you can't already read from the available Microsoft documention. Note the low page count!
Microsoft Dynamics AX 2012 Services - Available for pre-order
I'm one of the reviewers of this book, so I have already read it. I can really recommend this book to anyone who needs to work with services in AX.