purl.lib.lehigh.edu is a permanent URL resolver.
You must specify the ID of a URL within PURL's database to be redirected to the location of the resource, e. g.
Since you probably don't know the ID of such a resource off hand, you probably didn't mean to come here directly.
Most of the users of PURL end up coming here (briefly before being redirected) from links in Lehigh University's Library catalog.