I will assume you are talking about a Civil 3D 2006 courseware book. There are a few I know of to choose from. You can purchase Autodesk AOTC courseware by locating an Authorized Training Facility and purchase it through them.
http://usa.autodesk.com/adsk/servlet/index?siteID=123112&id=3001477
You can also check out Rick Ellis's book, he is a great guy and a great author!
http://www.cadapult-software.com/store/product_info.php?products_id=26
Hope this helps!