Monica found this very informative article; http://www.npr.org/templates/story/story.php?storyId=6551175
Celeriac is one of my favorite winter vegetables. It is versatile, flavorful and also very healthy. It can be a little intimidating if you have never worked with it before, but practice and patience will yield a very beneficial addition to your vegetable repertoire.
Typically you would peel the root with a knife rather than a peeler. I find it best to cut off each end so it will sit on a flat surface while you trim off the sides. Discard all of the peeling and rinse the root in cold water. From here your options are limitless. You can blanch it lightly and use it in a salad or cold application. You can cut it into perfect dice and cook it with a vegetable soup.
In addition you could take your puree and thin it with a little water and turn it into a looser, milk or cream like substitute. This can be very beneficial in making vegan or vegetarian soups or sauces. I haven't yet but I will do a little more homework and try and use this cream substitute in other applications as well.
As I said in the very beginning your option are limitless so if you find something works well, go with it, and share it with us.