Gwendy's Button Box (2017) by Stephen King and Richard Chizmar

Gwendy's Button Box (2017) by Stephen King and Richard Chizmar: In 1974, twelve-year-old Castle Rock native Gwendy Peterson meets a man in black sitting on a park bench. He's peculiarly convincing but no pervert. No, he wants her to take on stewardship of a peculiar small wooden box covered with buttons. She's the best person for the job. And as compensation, the box dispenses rare silver dollars on occasion and one exquisite chocolate once a day.

So begins this peculiar, affecting coming-of-age novella/short novel (it's really an abbreviated kunstlerroman). King handed it in unfinished form to writer-editor-publisher Richard Chizmar, who came up with ways to finish the narrative. The two work seamlessly together. The prose is a bit leaner, perhaps, than the King norm, but I'd be hard-pressed to figure out who wrote what.

The gem here is the character of Gwendy, who is perfectly believeable in the midst of increasing weirdness centered on that box and those buttons. As to who the Man in Black is -- well, I'll leave that to you. He sure does like the word 'palaver.' 

The horror in Gwendy's Button Box is mostly quiet and psychological, though King and Chizmar do throw in one gross-out scene, a brief one. In all, a rewarding, short read. Recommended.