Constructing a functional system of magic that helps readers suspend disbelief is a crucial part of worldbuilding in the fantasy genres. Yet creating a believable, compelling and original fictional universe can be daunting. To help inspire writers, this guide provides an overview of how magic has been understood in history and used in myth, legend and modern fiction. Different forms of magic are explored and a broad range of stories--from Nordic myths to modern novels--are described and referenced. Discussion explores how magic as a concept shapes, and is shaped by, fictional worlds and societies.