Graphic Novel
Published as
Empire Volume 2: Darklighter.
Check availability & pricing at:

These stories are included in:

Omnibus: At War with the Empire - Vol.1
(The Short Happy Life of Roons Sewell)

and

Omnibus: The Other Sons of Tatooine
(The Saga of Biggs Darklighter)

Comic Book series
Published May, July, September, October, December 2003 as Empire #8, 9, 10, 11, 12 & 15
by Dark Horse Comics:

Issue #8Issue #9

Issue #10Issue #11

Issue #12Issue #15

Limited Edition Hardback cover
Published September 2007 as
Volume Seven: Darlighter of Dark Horse
Comic's 30th Anniversary Collection

e-Comic Books
Published 2011
by Dark Horse Digital.

Synopsis:
This book collects together the following comic stories

• The Saga of Biggs Darklighter
  Few people know is that before the fateful Battle of Yavin, Luke Skywalker and Biggs Darklighter were childhood friends. In fact, it was Luke's dream to follow Biggs to the Imperial Academy. But what Biggs learns from his time with the Empire pushes him to become one of the earliest heroes of the Rebellion. 
  As a newly commissioned officer in the Empire, Biggs Darklighter is assigned to the frigate Rand Ecliptic. In his new post he learns that expediency is preferable to honesty, and that the deaths of innocents is an acceptable price to pay for covering one's mistakes. Horrified by what he has seen of the Empire in action, Biggs and a circle of his close companions plot to desert their posts and join the Rebellion. But when their plan is uncovered by another officer, desertion becomes a fight for survival!
  After the mutiny on board the Rand Ecliptic, Biggs Darklighter and his companions finally are able to make contact with the Rebel Alliance. The Rebels desperately need skilled pilots like Biggs and his friends, but it's hard to fight the Empire with the outdated fighter craft they have on hand.
  A plan is hatched to "liberate" several squadrons of X-wings, but until the Rebels get their hands on the new fighters, their only hope is pluck, luck, and the skill of pilots like Biggs Darklighter... 
  To Biggs Darklighter, it seems like he's already lived a lifetime of adventures since joining the Rebel Alliance. But now, reunited with his boyhood friend Luke Skywalker, Biggs faces what will prove to be the adventure of his life and his death: the assault on the Death Star!
  Occurs weeks before and during the Battle of Yavin.

• The Short, Happy Life of Roons Sewell
  General Dodonna was one of the Old Republic's most brilliant strategists. Now he must use all of his knowledge and all of his tricks to outwit the commanders of the Imperial fleet, many of whom were trained with his own tactics!
  To give the fledgling Rebel Alliance time to consolidate its forces, Dodonna chooses as a base an ancient, deserted temple on a moon orbiting a gaseous planet. But setting up Yavin Base is complicated by the need to raid Imperial convoys, internal squabbles among the Rebel leaders, and by the monstrous creatures who have also laid claim to the temple!
  While establishing the Rebel base on Yavin IV, General Dodonna clashes with fellow Rebel commander Roons Sewell over plans for the future of the still fledgling Alliance. Sewell is a charismatic leader who has won the hearts and minds of the rebel rank and file, but his flair for the dramatic worries the more pragmatic Dodonna. It's age and experience versus youth and vigor. But with the Empire searching for the new base, and ready to swoop in and destroy the rebels at the first opportunity, the behind the scenes struggle between Dodonna and Sewell could have unexpected and unwanted results for the Alliance!
  Occurs weeks before the Battle of Yavin.

Related Stories (in chronological order):

• The Short, Happy Life of Roons Sewell
• The Saga of Biggs Darklighter
• Rogue Squadron 1/2 by Michael A. Stackpole et al.
• A New Hope by George Lucas