I started reading The Sandman Companion yesterday in conjunction with my Sandman re-reading project. I bought this hardcover of analysis and opinion upon its initial publication 10 years ago with the intention of reading it along with some future re-reading of the entire series. I slogged through the opening chapters last night; they were very much intended for a different audience than I represent, explaining whay a comic book is and why one should bother reading one. It was a good section for non-comics readers (don't get me wrong), but I have higher hopes for the analysis itself.
It does relate an anecdote of Neil Gaiman's I found amusing, though (which I just discovered I can't do justice to relating off the top of my head; you'll just have to take my word for it).
Read the "Whatever Happened to the Caped Crusader?" two parter, plus a couple of the older stories from the back of the collection. That was certainly a Gaimanesque ending...but not very satisfying. I'll have to read it again, though, if only to more fully appreciate all of the period references in the art. For those who have been reading the Batman titles: did this give a reasonable conclusion to the final storyline in Batman & Detective Comics?