on to always clean up the book directory for you.
```



To do this:


```r
bookdown::clean_book(TRUE)
```



.footnote[
this is the default setting (clean = TRUE) for `render_book`
]


---
name: section
class: middle, inverse
background-image: url(img/kelly-sikkema-450720-unsplash.jpg)
background-size: cover

---
name: outline
template: section

.right-column[
# &lt;i class="fas fa-feather-alt"&gt;&lt;/i&gt;.fancy[Outline]

+ Preface: [the `index.Rmd`](#index-YAML) &lt;a href="https://bookdown.org/yihui/rm