Book of Types

There's a cool book that started reading about type-level programming: https://leanpub.com/book-of-types

Here's the cover text:

"This book aims to be the comprehensive manual for type-level programming. It's about getting you from here to there---from a competent Haskell programmer to one who convinces the compiler to do their work for them."

I wanted to talk about this book but also about type-level programming in general. What have you done with it? What are good use cases?