FRESH AIR: Ever since he was a kid, director Mike Mills has yearned to understand his mother. Mills, who was born in the ’60s, describes his mother as a “secretive soul” who was different from all the other moms he knew. “She was 40 when she had me, [and] she really did sort of walk and talk like Amelia Earhart and Humphrey Bogart put together,” Mills tells Fresh Air‘s Terry Gross. “I was always trying to figure out what her deal was.” Mills’ latest film, 20th Century Women, is inspired by that yearning. Set in Santa Barbara in 1979, it stars Annette Bening as Dorothea, a 55-year-old woman who grew up during the Depression and is struggling to raise her teenage son, Jamie, on her own. The director acknowledges that his mother, who died in 1999, was a private person and might have been resistant to a movie about her. He says he grappled with her spirit while he was writing the film. “My mom is a very tricky ghost,” Mills says. “At one certain point, there was a conversation with [her] ghost that went something like, ‘OK mom, … I’m sorry, I’m just going to do this, and I know that it’s filled with enough love and enough understanding that I feel like if I ever see you again I can defend myself — or I can deal with your ire.’ ” MORE