It depends on the library. For example, you won't be able to use Open XML SDK from Silverlight - it is only available for the .Net Framework. However there are number of custom implementations of OpenXML Standard in Silverlight.
Example from CodePlex:
This is a Silverlight proof of concept application that takes a simple Word document and displays it in the form of a book.
http://openxmlpageturn.codeplex.com/
Example from CodePlex:
This is a Silverlight proof of concept application that takes a simple Word document and displays it in the form of a book.
http://openxmlpageturn.codeplex.com/
