Well, for my own experiences and memories...

The first series of book, which had a deep and fundamental effect on me as a young child (when I was like 8 years old) is a series of scifi/fantasy books written by a Belgian writer (no idea if they are translated to English) called Philippe Ebly. Not his books contain any really deep message, it's just groups of teenagers having adventures, but those books deeply affected me because they are those which made me a book-eater. It's the first time I spent a whole Sunday devouring books.

Then I started much more of science-fiction, mostly from French writers like Christian Grenier, Jules Vernes and René Barjavel. I think that latest are the ones who influenced me the most at that time - Jules Vernes for his focus on science and the "miracles" of science, his heroes being engineers or scientists, more than anything else. And Barjavel for the ethical implication of technology and the sheer horror of war (especially in La Nuit des Temps ).

Later on, as a teenager, I also got very deeply impressed by Isaac Asimov, the Robots and the Foundation cycle. The scientific, rational approach of human societies that constitutes Psychohistory had a great call to me (even if I'm aware it's scifi and not fully realistic), into the power of reason, and the fact it can be used for anything, including improving the social structure of the society. And the way the Zeroth Law is devised by the robots in "Robots of Dawn" and "Robots and Empire" really struck me as a great analogy to how humans can, from selfish and stupid evolution, build an ethical system. The last sentence of "Robots and Empire" (hrm, I've only the French version with me, but re-translated from French to English it would be something like « And he was alone... alone to protect a whole galaxy. »), read as a teenager, played a very significant role in giving me something to protect. That, and LOTR message that « even the smallest person can change the course of the future ». Of course, those were teenage dreams, I'm aware things are not that easy in real life. And that many who tried to change the future did, but not in the way they excepted at first. But still, this teenage message is the foundation of what I've to protect.

But, more than any specific book (even if those books did play a huge role) I think that it's the huge number of books I devoured that shaped me. Each book forces you to identify and empathize with very different characters - a robot there, an alien here, a young slave there, a young prince here, a normal person who unwillingly become an hero there, a normal person who just ends up being convinced of a crime he didn't commit here, a really guilty criminal who still his a person with feelings, love and suffering there, ... That really did a lot to my ability to empathize with real-life humans, to not be too quick to label someone "evil", to try to understand people's real motives and ways of thinking before judging them, which is a fundamental thing if you want to be able to steer the future without completely botching it.