Oh, very much +1 for O'Brien. His works (like John Le Carre's) really amount to minor literature, so well does he depict character and the way it drives action and reaction, for his technical knowledge of fully-rigged sailing (he has been praised for accuracy by sailors, apparently), and his light but compelling style with a tongue in cheek quality that does not diminish the drama.
Le Carre's earlier works, particularly the Karla Trilogy and up to about Absolute Friends. I don't think his earliest or his later books are as good. And you can find the BBC's excellent dramatization with Alec Guiness; far better than subsequent adaptions, IMO.
Bernard Cornwell's Sharpe series. Cornwell is not at all as good as O'Brien or Le Carre, but he's good enough historically and literarily; but avoid his medieval stuff that is just psychologically and emotionally anachronistic; people didn't think like that in the "dark" or middle ages. And since characterization drives plot and action ...
BBC or some British TV company dramatized the Sharpe series and did it well.
MacBeth. MacBeth is a very modern character, but one that fits with the chronological setting as someone who bets his soul on advancement only to see it, very consciously and clearly, all slip through his fingers despite horrible crimes committed to preserve it, and he can find no other recourse than to continue pursuing his destructive course.
Enough literary criticism. But there is so much good adventure fiction available.
Patrick Moore, who was raised without TV in various places by a MLS mother and a father who at one time managed the Library of Congress's Stack and Reader Division before managing some of the library's overseas offices.