Don’t you swoon at the opening scene of “Mank,” in which Gary Oldman, playing kinda-legendary screenwriter Herman J. Mankiewicz, is deposited in a desert hideaway with a nurse and typist, in order to deliver post-haste the screenplay of Citizen Kane to outcast director/actor Orson Welles? Well, if you don’t swoon, Mank is not for you. But for the rest of us, this is an ancient-but-topical tale that David Fincher unwinds with unerring discipline. Oldman is outstanding as the unkempt, alcoholic, B-grade writer on the outer, spewing out from his bed the Welles’ classic, but all the actors fit in perfectly, with special credit due to Charles Dance (a malevolent, amused William Hearst) and Amanda Sayfried as his trophy bimbo actress. Cinematographer Erik Messerschmidt creates a sumptuous black-and-white, sharp-but-smoky visual feast, and everything about the movie achieves the aim of making a movie about the making of a movie in the very style of that movie. I gather the narrative messes slightly with the history, but who cares? The way that Fincher embeds the plot in an arc of tilting against the evil media magnate and his Republican vipers is breathtaking. If anyone asks me to accompany them on a second viewing, I shall jump at the chance, and I commend Mank to you.