format strings file I/O; saving and restoring state and data lambda OOP, overloading list comprehensions break, continue scopes, object reference rules tuple dictionary object methods/properties standard library tour documentation (writing) documentation (reading) code re-use, modularity, generality idioms and patterns abstraction levels efficiency function argument details raise/try/except pass algorithms and data structures specific libraries/corners of things: GUI network, IPC file spawning other programs CGI databases