Black and Blue Magic by Zilpha Keatley Snyder

In my quest of "gentle reading," I've been picking up more books from the Young Adult and Junior Reading sections of the library.

I heard about Black and Blue Magic when Gretchen Rubin was on Modern Mrs. Darcy's podcast.
(It's episode 52.)

Harry Marco thinks that it's going to be another boring summer until a mysterious traveling salesman moves into his family's boarding house. Magical, adventurous, and sweet.