As the most eloquent art about childhood often does, Janet Planet resides in the hazy certainty of memory. Acclaimed playwright Annie Baker has acknowledged that this work, her screen directorial debut, is autobiographical in origin. That illumination isn’t really required. The film radiates personal recollection in its every detail, from its chronological setting in a not-so-distant past that is rendered subtly, suggesting the story is place in that time for no other reason than its the time when it genuinely took place, to the accumulation of small details and impressions that become experience only through accumulation. The film follows a quiet, inquisitive, lightly lonely eleven-year-old girl named Lacy (Zoe Ziegler) through one summer living with her hippie-ish mother (Julianne Nicholson) in rural Massachusetts. People come in and out of their lives, Lacy practices songs on her electronic keyboard, and dust motes dance in the air. Baker’s director is spare, lovely, and patient. She favors image over explanation. The film feels like a work created by a keenly observant artist liberated from the demands of filling pages with stage direction and dialogue, who can now put the simplest, truest version of life as she sees it in front of an audience. Baker has many avenues available to her to tell her stories. She makes it clear that cinema was the only was she could tell this one.