Ah, yes, 007. Much as he is associated in the main with the vodka martini (shaken, not stirred, yada yada...), the first drink he orders in Casino Royale** is, in fact, an Americano! It reappears in From Russia with Love and again in the aforementioned novella, and as a long-time Bond fan, Fleming's drink-related authorial influence has clearly rubbed off on me.
1 part Campari
1 part red vermouth (rosso)
sparkling, or soda, water - to top up
Mix the Campari and vermouth in a highball (i.e. tall) glass. Top up with fizzy water. Drink deeply, considering the possibility of another.
**It should be taken as read that I refer, above, to the novels and not to the films. Fleming was much more exacting about the drinking habits of his most famous character than United Artists or MGM have ever been (apart from the, frankly, now oft-repeated, almost hackneyed martini-ordering sequences which seem to recur almost constantly (or is that just how it feels to me these days?). Sorry, geek rant over...