I don't know if this is outside of the scope of your plans, but threading issues are a big one that jump out for me. POSIX threads can cause all kinds of wonderful headaches, it would be nice to see some solid advice on the does and dont's.
I plan to follow Zed's model for 52 exercises, I don't see any reason why I shouldn't cover multi-threading and a perhaps a few different concurrency models in the latter half.