The subtitle of this book is "Selected Nonfiction," but it runs to a full 500 pages, so there's a lot that made the cut. Be prepared if you read this book to read more than that 500 pages, because Gaiman is his usual generous self here, and points you to so many other works of art that you'll be making library holds and Googling public domain short stories as you go. Thanks to this book, I found "The Gardener" by Kipling and "The Door in the Wall" by H.G. Wells, two excellent short stories that show underplayed sides of each of their respective writers. When Gaiman says something's especially good, it is indeed especially good.
The Yankees' legendary closer, Mariano Rivera, would freely show other pitchers how to throw his special cutter. He would try to give it away (yet he was always the master of it himself). Gaiman is the same way here -- he's trying his best to give away the secrets to making good art, and he explains it clearly several times over. Here's to some of it sinking in.
The organization of this book is also very good. It is a little overwhelming, and I would have cut about one or two essays per section, but the most recent stuff is the deepest and is concentrated in the last section, which deals with life and death. Despite the fact that this may seem to be "just a collection," it has a definite arc and a worthwhile climax in the last 50 pages.
For all that, it's ultimately a scrapbook, like The Art of Neil Gaiman by Hayley Campbell but with words only and from Gaiman's own pen. It's as worthwhile as most of Gaiman's writing -- which is to say, very.