Here is a list of all topics with brief descriptions:

Audio module	Sounds, streaming (musics or custom sources), recording, spatialization
Graphics module	2D graphics module: sprites, text, shapes, ..
Network module	Socket-based communication, utilities and higher-level network protocols (HTTP, FTP)
System module	Base module of SFML, defining various utilities
Window module	Provides OpenGL-based windows, and abstractions for events and input handling