Earlier this year I told you about Ben Ari's tell-all book about the new Unified Remote Access role in Windows Server 2012 which has large focus on DirectAccess as well as VPN, NAP, and more. This month Jordan Krause will be publishing a new (shorter) book that is specifically focused on Best Practices and Troubleshooting for DirectAccess.
Order yours at Packt Publishing
I had the pleasure of getting a sneak peak at the content because I was a technical reviewer of this book along with Richard Hicks, and I am not ashamed to tell you that I too learned a number of things by reading it. I think you'll find it a relatively quick read and a great reference.
If you're planning on standing up a DirectAccess deployment, or if you just want to know the why and how you can do DirectAccess the best way, this is the book for you (and me!).