In the books, Doctor No explains his name: "Doctor" obviously comes from his advanced education; "No" comes from his own father's complete and total abandonment of Doctor No as a child.
I've not read You Only Live Twice
yet, but from the film alone the title's origin is quite obvious -- Bond is "assassinated" in the pre-titles tease, only to be "resurrected" for his mission.
"The World is Not Enough" comes from the Latin translation, roughly modified from the direct translation "the world is insufficient," which is the Bond family credo, and seen on his family crest.
Mr. Laser Beam wrote:
Quantum of Solace is a reference to the fact that even if Bond gets revenge against those responsible for Vesper's death, he won't get much satisfaction from it. Only a tiny amount - a "quantum" of solace.
That's the context of title in the film, there's more to it regarding the short story, and though it may not be as "exciting" a context as that for the film, the original context of the title from the short story is much more human, much more believable.
The short story starts with Bond being bored and annoyed at having to go to some dinner at an island governor's house. There, after the party, Bond notices some chatterbox old lady and her husband, and is further annoyed by the simplicity of the evening. There's no excitement, no derring-do. Just coffee and dessert. BORE-ING. The governor tells him a story all about a woman who came to the island years ago as flight attendant and met one of his officers, a bookish, nerdy guy.
Eventually they got married, but it wasn't long before she began running around on her husband, going from affair to affair while everyone on the Caribbean Island they lived on knew about it except her husband. This goes on for years until finally the husband goes away on assignment. He returns, and promptly explains to her in no uncertain terms that they will remain married publicly, but that they will sleep in different beds, she will do all the house-cleaning, and take care of the domestic responsibilities of home. They will not vacation together, they will not even eat together. He had lost all empathy and affection for her, and being that she was otherwise penniless, she had to comply.
This goes on for years, after which the husband finally divorces her after selling off his house and property, and leaves her behind --broke, homeless and with nowhere to go. He's never heard from again.
Bond then asks what happened? Why didn't the husband help her out, even if he was going to leave?
The governor tells him there are some evils people commit that are so awful, so hurtful to us that they can't ever be forgiven. For a relationship to work, for a romantic relationship to work especially, both partners must have a quantum of solace -- that tiny spark of empathy for this person you love-- to continue to work through whatever hardships may arise. The officer clearly had reached a point, thanks to his now-ex-wife's shenanigans where the quantum of solace -- that last spark -- had been snuffed out entirely.
Bond shrugs it off, but reconsiders when the governor reveals that the destitute flight attendant who had so horribly scarred her husband after all those years of cheating on him was in fact the elderly, chatterbox woman Bond had met earlier. Bond is renewed with enthusiasm about the more mundane aspects of life, seeing again that even though some people can put up a good facade, just underneath all of us is a dark underbelly of our baggage, our sins, and our mistakes.
I might be misremembering some details, but that's the gist of it.