Celery root is a type of celery. It is actually not the root of a celery plant. It tastes somewhat like a potato.
When buying celery root, look for one that is heavy for its size. If it has stalks make sure they are green and fresh. For ease of peeling, pick one that has less grooves. You may keep celery root by wrapping it in plastic and placing in the fridge.
Celery root does well as a potato substitute or addition. It holds up well to all types of cooking. You can make a delicious creamy soup similar to cream of potato with it.