Star Wars has finally revealed how Luke Skywalker escaped Darth Vader for so long. When the Dark Lord of the Sith learned the name of the pilot who had destroyed the First Death Star, he resolved to find Luke Skywalker at all cost. Marvel's Star Wars comics have revealed he redoubled his efforts after Luke rejected him in The Empire Strikes Back, stung by the rejection and seeking vengeance.
The forces arrayed against Luke Skywalker were impressive. He was essentially the most wanted man in the galaxy, with Imperial Intelligence looking everywhere for him. The Empire would have been willing to compromise any of their informants in order to get their hands on Luke, so he'd have been in danger every time he visited a Rebel base. And he wouldn't have been any safer traveling the galaxy alone, on various quests to learn how to use the Force, because the Empire had presumably put an expensive bounty on his head. And yet, somehow, the farmboy successfully evaded his pursuers - both Imperial and bounty hunters - until Return of the Jedi.
This week's Star Wars #5 finally reveals how Luke managed to stay free. The issue opens with a cocky young pilot in a bar bragging to his clients that he is Luke Skywalker, the man who shot down the First Death Star. "If I can blow up a Death Star, I can get your little shipment where it's going," the pilot boasts. In reality, of course, he's just a smuggler who's down on his luck, and who happened to visually resemble Luke. He's a Luke Skywalker impostor who has taken on the name on in the hopes of impressing potential clients. Unfortunately it draws the wrong kind of attention, when Darth Vader walks in, Force chokes him, and strides out of the bar after warning anyone that to claim the name Skywalker is to choose a death sentence.
It seems this isn't the first false lead Darth Vader has chased down. The name "Luke Skywalker" has become a legend among the galaxy's pilots, and countless people have hit upon the idea of capitalizing on that by claiming the name for themselves. Given these are all pilots, they'll be traveling the galaxy, moving from planet to planet. That means any one Skywalker impostor could generate dozens of false leads, occupying Imperial Intelligence and any bounty hunters. Presumably this particular rumor was considered believable enough to notify Darth Vader directly - but the Sith Lord's warning suggests he's been called in before, and is getting quite fed up of it.
The galaxy is a big place, and it's much easier to hide when there are an unknown number of people pretending to be you. Ironically, Luke's very fame protected him from Darth Vader's wrath - and ensured he had the chance to survive until Return of the Jedi.