Mike Mills' texturally and behaviorally rich new comedy seems to keep redefining itself as it goes along, creating a moving group portrait of particular people in a particular place (Santa Barbara) at a particular moment in the 20th century (1979), one lovingly attended detail at a time. The great Annette Bening, in one of her very best performances, is Dorothea, a single mother raising her teenage son, Jamie (Lucas Jade Zumann), in a sprawling bohemian house, which is shared by an itinerant carpenter (Billy Crudup) and a punk artist with a Bowie haircut (Greta Gerwig) and frequented by Jamie's rebellious friend Julie (Elle Fanning). 20th Century Women is the kind of wonder that only comes along once in a blue moon. It's a portrait of director Mills' mother and serves as unofficial companion to his multiple award-winning Beginners, which dealt with the late coming-out of Mills' father. It's a work of passionate artistry filled with with the kinds of people you know very well or ones you would like to know. Warm and achingly funny, by the time it reaches its conclusion, you'll want to hug the person who made it.