Our Movie Critic's Weekend Selections

Mistress America A screwball comedy about female friendship, betrayal, and theft starring the crazily gesticulative Greta Gerwig as a know-it-all New Yorker who decides to mentor a lonely college freshman new to the big city, played by Lola Kirke. Noah Baumbach directs from a screenplay on which he and Gerwig collaborated, between breaks watching Howard Hawks and Preston Sturges. R

Best of Enemies William F. Buckley Jr. and Gore Vidal - righty and lefty intellectuals, respectively - square off on camera, offering commentary on the 1968 Republican and Democratic National Conventions. A bracing view of a pivotal time in politics and TV news, as Vietnam and race riots scarred a nation's soul, as the establishment and the counterculture exchanged epithets and blows.R

The Diary of a Teenage Girl A 15-year-old in freewheeling '70s San Francisco has an affair with her mother's boyfriend in this honest and unblurred examination of a tricky voyage into womanhood. It may sound scandalous, or exploitative, or deeply inappropriate, but the film - written and directed by Marielle Heller, adapted from Phoebe Gloeckner's graphic novel - is none of those things. Bel Powley stars, with Kristin Wiig and Alexander Skarsgård. R