1992 brought us Dark Force Rising, the second book of Timothy Zahn's Thrawn Trilogy. Slightly generic title aside, it expands on the previous entry and further expands the lore and setting of the nascent Expanded Universe by dipping into relics from the Old Republic.
At this point, both the New Republic and Grand Admiral Thrawn's Imperial remnant are bloodied and looking for an edge in their fight. The NR is aware that there is an information leak, and Han Solo suspects the shifty Bothan senator Borsk Fey'lya and his Spynet connections and Lando goes along for the ride.
Meanwhile, Luke Skywalker is drawn to a planet where the mad clone Jedi Joruus C'Baoth is waiting for him, claiming to want to teach him. Luke soon realizes that C'Baoth is incredibly powerful and also a budding tyrant and wants to help heal his damaged mind. C'Baoth's goal at the moment is to train Luke, Leia and her unborn twins as Jedi molded by his fractured mind.
Meanwhiler, smuggler baron Talon Karrde is on the run after Thrawn learned of his duplicitousness. Karrde is eventually captured and imprisoned by the Admiral because he knows where a large supply of valuable warships are hidden. Mara Jade tracks down Luke and helps him shake off C'Baoth's mind tricks. Like it or not, she needs his help rescuing Karrde.
Meanwhiler-er, a very, very pregnant Leia travels with Chewie & Threepio to Honoghr, the planet of the Noghri that have been trying to capture her to try and win them over to the New Republic.
Meanwhilest, Han & Lando stumble upon a ghost: a Corellian Senator who's long been thought dead named Garm Bel Iblis. Not only is Garm alive and well, he's been running his own splinter Rebellion against the Empire after splitting off from Mon Mothma over ideological differences. Bel Iblis is a tactical genius and has a line on some long-lost warships, but he's not one to rejoin the New Republic without some serious convincing.
It all ends in a race to find the location of a fleet of fabled Dreadnaught-class heavy cruisers called the Katana Fleet.
This is going to be a broken record, but Book 2 continues to do what Heir to the Empire did so very well: Grand space opera in the vein of the original Trilogy. World-hopping, action, tactical genius, new technologies, and adventure.
Of the two major new characters, Garm Bel Iblis fits into a kind of character archetype that Zahn is fond of: the highly intelligent master planner. Talon Karrde & Thrawn are both extensions of that. This is fine, since Zahn does them very well and differentiates their personalities and areas of expertise, but there are a lot of clever bastards populating this book.
This is balanced out by the other new character: Lowbrow ship thief Niles Ferrier. Ferrier is a scumbag who's only really good at one thing: stealing starships, and Thrawn wants him to find ships for the Empire. Unfortunately Ferrier thinks he can hang with the big boys, and fancies himself a master schemer. Amusingly enough, he's not.
Before I say “Its a good book, read it if you like Star Wars” I think there's room to discuss a few established characters.
Leia goes behind enemy lines to do what she does best: diplomacy. She's able to go into hostile territory protected by secrecy and her heritage as Darth Vader's daughter. Spoiler: she succeeds, without firing a shot and while heavily pregnant. Its remarkably well handled and shows just how powerful and essential to the New Republic Leia is.
Next, is Luke. Being a Jedi, Luke fights a lot, but this trilogy really hammers home the idea that its only ever as a last resort. Knowledge and Defense, never Attack, that sort of thing. Even when he learns that C'Baoth is completely mad, he doesn't want to kill him. He wants to help him, not kill him. Luke is a capital-G Good Guy, and has the skill and wisdom to pull it off exceptionally.
Dark Force Rising is a good book, read it if you like Star Wars. It continues the top tier entertainment of the Thrawn Trilogy.