2 oz vodka because much of the time, he was a spy with Russian adversaries and he wanted to blend in, also note that he doesn't specify which vodka because he actually doesn't care. 1 oz Gordon's because beneath all that he's a true red blooded Brit and he'll always proudly drink British gin. Lilet Blanc because it's not his money and he's surrounded by wealthy people so he might as well buy the most expensive vermouth in the world. Shaken not stirred because he wants the drink to be cold, causing him to drink more slowly, and because it will water it down, meaning he will appear to be drinking more than he actually is and people will underestimate him. I can't figure out any obvious subtext for the lemon twist, but it is a very classy way to have a martini. Call it a Vesper to memorialize his first love, and emphasize that he doesn't and can't have a life outside of being a spy, he's condemned to this world.

The Vesper is the best fusion of lore and a cocktail you could ever conceive and will never be topped.

The Vesper is James Bond's personal invention, from the very first novel, Casino Royale. It's basically his own custom twist on the vodka martini.

He explains he only has one drink before dinner, but he prefers it's a large one, ice cold, and made very well. He drinks plenty of other types of alcohol throughout the books, but he's pretty particular about this one evening aperitif.

The movies kind of latched onto it and just made him drink vodka martinis in general. Although the 2006 film Casino Royale had him order his custom invention from a bar, almost word-for-word from the original novel. It's named after Vesper Lynd, the first girl Bond truly fell for in the novels.