Most readings are available online. I will include links to them.
Many are accessible from the ACM Digital library.
To gain access to this, you have to go in via the special UIUC entrance so that you
can be authenticated as a UIUC student.
You really need this one:
Carroll, J.M. (2000) Making Use: Scenario-Based Design of Human-Computer Interactions. MIT Press. ISBN 0262032791
If you are very keen and interested, these are also well worth reading:
Cooper A (1999) The inmates are running the asylum. SAMS Indiana
Rosson, M.B. & Carroll, J.M. (2001) Usability Engineering: Scenario-Based Development of Human-Computer Interaction Morgan Kaufmann. ISBN 1558607129
Online access to CS Journals via UIUC Library