1982 Janine is Gray's best book (and his own favourite) but is difficult to get hold of, Lanark is his most important but difficult to get through, Poor Things is his most successful but not weighty enough. Unlikely Stories, Mostly is just right -- like Little Bear's porridge.
This book is more an anthology of Gray's early works than a collection of stories. One was written when he was 15, others were written when he was at Art College. Considering he was 46 when it was published, there's hope for all of us. Highlights are Five Letters From an Eastern Empire, a masterful portayal of censorship in art and the control a dictatorship can have on creative minds; the Tale of the White Dog, after reading it you'll be more enquiring about your potential in-laws; and The Cause of Some Recent Changes.
Some dislike the long central story Logopandocy. However if, before reading it, you know it is about a real person and the high-falutin' dense, sometimes willfully obscure, language accurately reflects Urqhuart's own writing (in fact, tones it down considerably) you may enjoy it more.
But despite the writing itself, the book would be a joy to own just for the way it looks. The paperback is a poor substitute for the original hardback, but is still one of the most beautiful mainstream publications you can own. The original had a slip inserted, which said "Erratum: This slip has been inserted by mistake". The whole is smothered in Gray's own wicked illustrations, inspired by Blake, Eric Gill and Stanley Spencer. I can't really recommend this highly enough.