The book opens with a middle aged man returning to his childhood neighbourhood for a funeral - but the vast majority of the book is a story of his childhood that he only remembers when he returns there. It's a distinctly creepy story, set in our world but drawing in other fantasy worlds.
It's well written. It's Gaiman, whose English prose is usually (as here) simple and extremely effective. It feels a bit like a story for children, but it's not. I'm good either way ... but I didn't like it. I suspect because the lead character was so passive: he is tormented and pursued, he hides and he waits. He does almost nothing to protect himself or improve his situation, just relies on others (but not his parents). Sure, he's way out of his depth ... but the passivity that this imparts to the story is why most stories lead with someone who's only a bit out of their depth and struggling to learn. That's easier to relate to and enjoy.
I also found the existence of the frame story fairly annoying: I get why he put it there, but the main point of it was to enclose and close off the childhood story, saying "childhood is a mystery we forget and don't understand in adulthood." It seemed unnecessary.