Few SF media tie-in series are as strong as the series of novels and stories based on the Star Wars movies. My experience with them is a bit limited: I haven't read any of the novels or novelizations based on the "prequel" movies or the Clone Wars. Most of my experience is with the original trilogy and the novels based on them.
The Star Wars book series started with novelizations of the three movies. While none of these are especially well-written, they're still good reads, and I think they add a lot to the movie experience.
STAR WARS (later retitled STAR WARS: A NEW HOPE) is the novelization of the original movie screenplay. It's basically the first movie's story as Lucas first envisioned it, before he had to start cutting it for various reasons. It adds a lot of depth that's missing from the movie, including Luke's friendship with Biggs Darklighter and some other valuable exposition and character-building.
STAR WARS: THE EMPIRE STRIKES BACK is Donald Glut's novelization of the second SW film. Like the first novelization, it's based on an early version of the script that allowed more depth, and includes several scenes that never made it into the movie. Most interesting are some additional scenes from Luke's Jedi training on Dagobah, which give more glimpses of how he learned to use the Force.
STAR WARS: RETURN OF THE JEDI is James Kahn's novelization of the third SW film. Like the first two, it's based on an early version of the script with more depth and more exposition, but there's not all that much of it and it sticks closer to the film as finally shown.
The Star Wars saga has a growing collection of tie-ins. I focus mainly on the novels. Maybe half the ones I've read have been worth keeping; the rest simply didn't work very well, and were off to the used bookstore shortly after I finished reading them. In some cases that's because they were badly written; in others, it's because the author misunderstood the Star Wars milieu. Star Wars isn't really science fiction, and trying to set strong SF in the Star Wars universe just doesn't work. The better Star Wars novels tend to be the ones that are non-SF stories transplanted to the Star Wars setting. Of the ones I've read, these are the ones I've thought good enough to keep:
SPLINTER OF THE MIND'S EYE
Foster, Alan Dean
c.1978, Del Rey
ISBN: 0-345-26062-7
The very first Star Wars-based novel, set between Star Wars and The Empire Strikes Back. Stranded on an Imperial-occupied planet, Luke Skywalker and Princess Leia Organa find themselves racing against Lord Darth Vader to claim a strange crystal that gives its holder tremendous mastery over the Force. Not the best Star Wars tie-in novel, but far from the worst. Foster's authorial touch is unmistakable, from the plentiful alien life-forms to the distinctive descriptions of characters and combat sequences.
Except for SPLINTER, most of the Star Wars novels I've read have been set after Return of the Jedi.
Timothy Zahn's trilogy was the first entry in the Bantam Spectra line of SW novels. Set about five years after Return of the Jedi, these three novels tell of a new campaign against the New Republic by the remnants of the Galactic Empire. The Empire's troops have reason to be confident: they're led by Grand Admiral Thrawn, one of the greatest military minds the Empire ever knew. The Zahn trilogy is considered by many to be the best of the Star Wars tie-in novels. I agree. The Zahn trilogy is one of the few examples of an SW novel being written the way SW novels should be written: as political-military thrillers of the kind made famous by Tom Clancy and Stephen Coonts.
- HEIR TO THE EMPIRE -- Five years after Return of the Jedi, the remnants of the Empire and its military have been taken over by new leadership: Grand Admiral Thrawn, the only non-human ever to reach that rank and the greatest military mind in the Empire. Thrawn has great plans for destroying the New Republic and restoring the Empire. To this end, he combines technology from the Emperor's "treasure-trove" world with several other elements, such as an insane Jedi Master and a creature which counters the Force and therefore makes Jedi powerless, and uses them to begin forging a grand new Imperial Fleet.
- DARK FORCE RISING -- Thrawn's complex, seemingly infallible plan begins to unfold, besieging the New Republic with assaults both real and imagined, from both within and without. Meanwhile, the Jedi Master Joruus C'baoth begins his own plan to trap Luke Skywalker and Leia Organa, and make them into his followers. For their parts, Luke and Leia and their friends find some new allies in unexpected places as they seek to rally the Republic against Thrawn's campaign. Unfortunately, they also find some new enemies, such as a power-hungry politician who will do anything and accuse anyone in order to increase his power base.
- THE LAST COMMAND -- Thrawn's plan is finally revealed in all its complex facets, and the New Republic finds itself faced with an enemy that is truly capable of defeating it. Thrawn's ingenious use of his cloaking technology has cut off the capital world of Coruscant and left the Republic scrambling to find countermeasures. While the Republic's Fleet plans a complex operation to neutralize one of Thrawn's traps, Luke, Leia, Han Solo, and allies old and new come together in a final confrontation with the mad Jedi C'baoth.
The X-Wing series, by Michael Stackpole, is a military action series in the same vein as Stephen Coonts's FLIGHT OF THE INTRUDER. The X-Wing series is set a couple of years after Return of the Jedi. It focuses on the pilots and support crews, the ones who actually do the fighting and the dying. There's also a lot of attention to technology and how the fighters and other spacecraft work. The main character is an X-wing pilot named Corran Horn, but Wedge Antilles, Rogue Squadron commander, gets a lot of time too.
- X-WING: ROGUE SQUADRON
c.1996, Bantam Spectra
ISBN: 0-553-56801-9
The New Republic is beginning its campaign to conquer Coruscant, capital of the now-leaderless Empire. To spearhead the assault, Commander Wedge Antilles reorganizes Rogue Squadron with all-new pilots and takes them into battle against the remnants of the Empire. Chief among the new Rogues is a skilled Corellian starfighter pilot named Corran Horn. The story follows Horn and the rest of the new Rogues through the selection process, flight training, and their first few missions, some easy and some not. - X-WING: WEDGE'S GAMBLE
c.1997, Bantam Books
ISBN: 0-553-56802-7
The pilots of Rogue Squadron become undercover commandos, trying to find a way to make Coruscant fall to the Rebellion without a pitched battle. Their task is made considerably more difficult by the growing suspicion that they have an Imperial spy among them. Meanwhile, Imperial commander Ysanne Isard is engaged in scheming of her own to make sure that even if the Rebels win, it will be a Pyrrhic victory. - X-WING: THE KRYTOS TRAP
c.1996, Bantam Books
ISBN: 0-553-56803-5
Coruscant has fallen, but the Rogues have paid a high price: Corran Horn is missing and believed killed. Now the Rogues must lead the fight against a new kind of enemy. Before Coruscant fell, Ysanne Isard loosed a virulent plague, codenamed Krytos, on its population. The plague is designed as not a military but a political weapon: it affects only nonhumans, and it can be easily cured with the healing fluid bacta. However, there's not nearly enough bacta to go around. So the Rogues must get more bacta by any means necessary. Meanwhile, unknown to them, Corran Horn is still alive and being held by Isard while she attempts to break his mind and turn him into a covert agent. Eventually Corran escapes, resulting in Ysard's departure from Coruscant in an almost unbelievable way. - X-WING: THE BACTA WAR
c.1997, Bantam Spectra
ISBN: 0-553-56804-3
Ysanne Isard has abandoned Coruscant and fled to the planet Thyferra, only source of the healing fluid bacta. With her Super Star Destroyer and three smaller ships, she's seized control of Thyferra and the bacta supply, leaving the New Republic critically short of bacta to fight the Krytos plague. The New Republic won't move against Isard ... but Rogue Squadron will. After resigning en masse from the New Republic military, Wedge Antilles and his pilots and friends are out to beat Isard and free Thyferra. To do it, they truly will have to do the impossible: starting with no base, no supplies, almost no ships, the ex-Rogues and a few unorthodox allies must somehow defeat Isard's fleet of a Super Star Destroyer and three Star Destroyers.
After finished the X-WING novels, Stackpole turned his attention to a singleton novel that focuses even more strongly and directly on Corran Horn.
I, JEDI
Corran wakes abruptly one night to the realization that his wife Mirax is lost -- lost not only to the New Republic, but also to Corran's growing Force-senses. To rescue her, he must fully accept his Jedi heritage, train as a Jedi, then infiltrate the renegades who captured Mirax and find a way to rescue her. I, JEDI is a rarity among tie-in novels, because it manages to be a good story while also significantly expanding on the shared universe in which it's set. It also includes material that connects with Tim Zahn's trilogy and with Kevin Anderson's "Jedi Academy trilogy."
Aaron Allston wrote three more X-WING novels, focusing on a second X-wing squadron called Wraith Squadron. Where Rogue Squadron is a squadron of fighter pilots who happen to have useful commando skills, Wraith Squadron is a unit of commandos who happen to be pilots too. Allston takes a different direction in his X-WING novels from Stackpole's straightforward military fiction. The three Wraith Squadron books are more character-driven, examining how the members of Wraith Squadron deal with each other and with their missions. It has a strong element of "the Dirty Dozen" in it, and for a while I didn't much like the first one because of that. But eventually I decided while these novels aren't great, they aren't bad either.
- X-WING: WRAITH SQUADRON tells of the Wraiths' formation, training, and first major mission against Imperial Admiral Apwar Trigit, a follower of the self-proclaimed Warlord Zsinj. After fleeing an Imperial attack on their training base, the Wraiths use some very unorthodox tactics to take over an Imperial corvette and become double agents, pretending to fly for Admiral Trigit while they also work against him.
- In X-WING: IRON FIST, the Wraiths continue their campaign against Zsinj from the inside. First they become pirates to draw his attention, then they join his forces as double agents.
- In X-WING: SOLO COMMAND, the Wraiths revert to their original role of pilot/commandos, working to undercut Zsinj in more conventional ways and also draw him into a trap where Han Solo's task force can defeat him. At the same time Zsinj is working to trap Solo's fleet, using information provided by a double agent.
