[1] He quips that: "The problem with Planescape is that it inspires an almost ceaseless tide of high-quality accessories, and such creativity puts a strain on both the finances and campaigns of referees.

"[1] Webb adds: "By expanding the accepted 'physics' of the Astral plane and applying classic Planescape thinking, the Silver Void is made solid and comprehensible.

Rules for astral travel, zero-gravity combat and spellcasting are crisply and clearly explained - all concepts that will add extra spice to normal play and properly emphasise the unique nature of this inner space.

Such depth is necessary because it's suggested as an optional player race, but while as non-player characters the Githyanki boast some excellent twists and Astral-specific spells, as PCs they would be little more than dextrous, not to mention ugly, egg layers.

Many of the monsters have been met before in other Planescape sourcebooks, but the locations are excellent, original work - the Bonecloud (a zombie swarm) and Divinity Leech (a fortress that sucks energy from the corpses of gods) take the bizarre nature of this plane to its logical extreme.