Or at least my local gaming shop got their copies in today. Sadly because of repairs I had to make on my car it will be about 2 weeks until I can pick up my copy. However the book looks truly awesome. I was only looking at it for about 5 minutes but seems to be lots of detail background info to add the crunchy stuff. There are lifestyle notes, Behavior information, pages on bodily structure, bones, organs etc. not to mention abnormal variations in styles/behavior. It all looks really cool and likely drop well into any Planescape campaign.
I will get the book and do a full review before the end of the month hopefully.
Apart from the Illithid, does this have a lot of material for Planescape? Are the gith races going to be detailed in this book?