Where can I buy the latest Northeast Corridor transit map?

There's a special map that shows the entire Northeast Corridor area and has all the information about Amtrak and local transit commuter train and bus service serving the NE Corridor area from Washington, DC to Boston. I don't know the exact name of the map, but I remember seeing it available last year on some websites (including Golden Spike Books, which no longer sells it) that sells railroad books, atlases and maps. I know it's still in print, but I couldn't find it available on any website. Maybe it's available (by back-order, if it's not in stock) at Barnes and Noble and other bookstores