Good reviews generally use a discursive writing style and are structured around themes and related theories. Occasionally the review may seek to explicate the views and future visions of different authors. LR involves the analysis of books, reports, journals or websites, and most often requires an expert in the topic concerned using their existing knowledge of the field to identify crucial contributions and synthesize their implications for the topic at hand (e.g. what they have to say about key drivers, alternative futures, policy instruments, etc.).