In Section 1.1.2, we learned how to create a new R script. R script is useful for organizing R code and add brief comments. However, to write document with more complicated structure, you need to use something more sophisticated. In this chapter, we introduce a new file format, namely the R Markdown file (.rmd). Using R Markdown, you can turn the data analyses into high quality documents, reports, presentations, books, and many other possible forms.