Once again I find myself writing a review on a game as opposed to a novel, but since this is included on Goodreads I should be allowed to review it. Mind you, they also included Ozymandias and Mister Dog so I must admit that on Goodreads, as long as it is written down, then it can be reviewed (though I haven't seen any reviews for street signs, or the Yellow Pages, yet, and no, I'm not going to be the first to do it, though I am tempted).
This setting was a setting that I was really looking forward too. By this time TSR already had three gaming worlds (Greyhawk, Forgotten Realms, and Dragonlance) and it appears that they were trying to explore new concepts. Personally, I say good on them. After having three stock standard gaming worlds, they really needed to consider creating some new and different worlds, and they began to do this. Along with this we also had worlds like Darksun, Al-Quadim, and Kara-Tur (though the last two are more extensions of the Forgotten Realms). With Spelljammer, TSR took gaming into space, but with a significant difference.
When I first heard of this I was anticipating something more like a hard science-fiction setting with magic thrown in, sort of like Star Wars. They had done this before with the Blackmoor series of modules and [book: Expedition to the Barrier Peaks] (both of these adventures included lasers, robots, and spaceships), however Spelljammer turned out to be completely different. It is difficult to understand how they linked these previous adventures to this new setting, but continuity isn't necessarily needed for a game, or even a game world.
This setting was much different to what I expected, but I remember running to the game store (which I was allowed to enter ... long story), putting an order in, and picking it up as soon as it arrived. I then returned to the State Library, ripped off the shrink wrap, and was stunned. The setting involved sailing ships, not metallic spaceships and robots. In fact there was no real technology involved, rather it was literally AD&D in space. However it was really helpful because not only did they have rules for spaceship combat, but you could also translate them to seaborne combat (its funny that they developed rules for space before they developed rules for the sea) as well.
As well as the standard races they also brought in number of new ones, such as the Negoi (half spiders and half eels). They also made the illithid (my favourite AD&D monster) into a much more common encounter in space. Propulsion was different as well. There was no warp drive or light speed, but rather ships were propelled by magic, and by magicians. Further, planetary systems were all contained in 'crystal spheres' which floated in a sea of strangeness called the Phlogiston.
This was different, and new, and after getting over my initial disappointment, came to really appreciate the uniqueness of the setting. This was pretty much unlike anything that had come out before, or since, though I do have a feeling that it was not all that popular, which is why it never made it into 3rd edition.