The Arcane Trickster is my favourite class. It is the ideal blend of rogue and wizard. It is so popular that it was moved into the OGL (the core books) when the system upgraded to 3.5. That allowed this book could be produced. Second Look: Arcane Trickster re-writes the Arcane Trickster into three new 20 level classes. Each focuses on a different element.
The Arcane Trickster of Ritual focuses on spellcasting and is most like the original. The Arcane Trickster of Deed focuses on skills and the sneak attack skill while sacrificing some spellcasting. The Arcane Trickster of Steel focuses on combat, sacrificing some skill and spellcasting ability for combat prowess. All the versions of this class have some spellcasting ability, access to the signature ranged legerdemain ability and the trapfinding ability.
This 38 page book includes 7 new prestige classes. Each of the classes and prestige classes include their epic progressions. There are 17 new feats geared for the arcane trickster and three new spells. Finally there are rules clarifying bonus spells and taking levels the four arcane trickster classes/prestige classes (go ahead!). A handful of NPCs and a short story rounds out this manual.
If you love the Arcane Trickster, or are just curious, come have a second look!