Thanks Sander, very nice compilation of books. In addition, I like several of these:

- User Story Mapping by Jeff Patton; great insights on how to use stories, especially highlights why we need them

- Extreme Programming Explained by Kent Beck; if you are a Scrum Master working on software, XP is the best complimentary framework to delivery valuable, quality software

- Escaping the Build Trap by Melissa Perri; essential read for Product Management, an area that a Scrum Master must also understand in order to work with the Product Owner and the organization