We've learned what d3.js is and took a glance at the core philosophy behind how it works. We've also set up a quick and easy environment for prototyping ideas and playing with visualizations. This environment will be assumed throughout the book.
We've also gone through a simple example and created an animated histogram using some of the basics of d3.js. We found out about scales and axes, that the vertical axis is inverted, that any property defined as a function is recalculated for every data point, and that we use a combination of CSS and SVG to make things beautiful.
Most of all, this chapter has given you the basic tools so that you can start playing with d3.js on your own. Tinkering is your friend.