A transfer of a patent that fails to confer a right with respect to excluding others from either manufacturing, using or selling a patent within the United States results in a license, versus a sale, of a patent. Whether all of the substantial rights to a patent have been transferred is a question of facts and circumstances. The measure of ascertaining what has or has not been transferred is to examine what rights have been retained by the grantor. When is Intangible Property Considered Like Kind?