The .pdf files (notably the course notes book) are restricted to
reading from within .ed.ac.uk. These files can only be accessed
if the request comes from within the University. For remote users,
this means either connecting remotely via an SSH client to
student.login.inf.ed.ac.uk, or browsing via an authenticated mechanism
such as the Informatics Web Authentication Portal:

     Use this site to login for School of Informatics web services from
     remote machines. "Remote machines" includes EUCS Open-access
     Computing Laboratory Workstations and home user personal
     computers.

(see http://www.inf.ed.ac.uk/systems/authportal, or
http://www.inf.ed.ac.uk/systems/support/FAQ/#AA0 for more general
remote access information).