Jan Dodonna is a General of the Rebel Alliance. Captured shortly after the battle on Yavin (first death star; he's the dude issuing orders and handing out medals in the movie). He was imprisioned on the Lusankya. He was found by Rogue Squadron member Corran Horn in the 3rd X Wing book and is set free in like the 9th X Wing book.
If I remember correctly he designed the A Wing prototype as well.