Fragile Things is a collection of stuff by Gaiman, covering nearly every size, from poem to novella. There’s a bunch of really good stories, like A Study in Emerald (a successful mix of the Chtulhu- and the Sherlock Holmes-universe), October in the Chair, The Problem of Susan, Goliath (a story set in the Matrix-universe) and The Monarch of the Glen (further adventures of Shadow from American Gods). Others in it are good too. Most of the shorter material I find less interesting, it’s more or less experimental stuff, trying out some odd ideas or narrative experiments.
Most of themes are common ground for Gaiman: fantastical elements with the modern world as a background, plays with established characters from other fictional universes, characters looking back and weighting their lives against the expectations of their youth, odd events and the nature of stories.
Everything is told in a detached voice that both distances from the worst of what actually happens to some characters and yet shows a compassionate narrator who hasn’t all the answers, but who is adept at conveying the magic of both mundane and fantastic things.