Contracts is a giant subject and there are many other library resources available.
Sum and Substance audio CDs and downloadable resources on West Academic.
Cases! Remember your casebook is composed of well. . . cases. Cases edited for clarity that is. Cases on Westlaw and LexisNexis contain case summaries written by the respective publishers as well as other editorial enhancements such as pulling out points of law to help a reader.
Podcasts, blogs and more are available online. For example:
CALI Podcasts (one of many on contracts)