Michael André-Driussi has written an interesting web article about what kind of science fiction served as the designers’ inspiration for the original “classic” Traveller role-playing game — link >>>

The real thing: some vintage Traveller books
André-Driussi pays particular attention to E C Tubb’s many Dumarest stories and H Beam Piper’s novel Space Viking.
I agree largely with his observations, though I have not read Space Viking, but I would ascribe more design influence to Jerry Pournelle’s Falkenberg stories (future mercenaries in action on rural planets), perhaps also to the John Grimes stories by Bertram Chandler (plenty of low-level espionage and trade among the stars). Also, when I GM’ed classic Traveller in 1978-82, I got a lot of thematically appropriate inspiration from gritty British action novels of the 1960s and 1970s, e.g. by Desmond Bagley (whose High Citadel can be transferred straight into Traveller.)
A while ago, I also wrote about Traveller inspiration, and about books (including Space Viking) that you now can download for free.
http://zho.berka.com/2011/04/12/traveller-inspiration-free-e-books/
Nice idea. 🙂