CFFI provides a rich and powerful foundation for communicating with foreign libraries; as we have seen, it is up to you to make that experience a pleasantly Lispy one. This tutorial does not cover all the features of CFFI; please see the rest of the manual for details. In particular, if something seems obviously missing, it is likely that either code or a good reason for lack of code is already present.
Implementor's note: There are some other things in CFFI that might deserve tutorial sections, such as free-translated-object, or structs. Let us know which ones you care about.