John announced a few weeks ago that Tai-Danae Bradley was working on a booklet from the ACT 2018 conference. She has finished the booklet, titled *What is applied category theory?* and it's now live on the [arXiv](https://arxiv.org/pdf/1809.05923.pdf) (and her [blog](https://www.math3ma.com/blog/notes-on-act)).

Hoping to discuss once I've read and digested it some!