Last year was an especially fecund one for films dealing with soon-to-be-empty nests. Between “The Kids Are All Right” and “Toy Story 3,” audiences were gifted with particularly sensitive portrayals of one of the most bittersweet passages in family life, when the first child prepares to leave for college.

Still, as wonderful as those fiction films were, they don’t hold a wry or wistful candle to “The Kids Grow Up,” Doug Block’s intimate, funny, deeply affecting diary of his daughter Lucy’s final year at home. In 2005, Block made “51 Birch Street,” a delicately layered portrait of his parents’ relationship while he was growing up in suburban New York in the 1950s. Like that film, “The Kids Grow Up” is both a close examination of family tectonics and a more universal depiction of a cultural moment. In this case, that larger zeitgeist has to do with a generation that came of age being obsessively videotaped by baby boomer parents who were often more interested in being buddies than authority figures. And, when Block’s stepson has a baby in the course of the film, “The Kids Grow Up” obliquely chronicles a cohort of men who, decades after the feminist revolution, are finally asking how to balance work and family.

“The Kids Grow Up” begins on a sweetly elegiac note, as Block’s young daughter Lucy practices ballet steps in front of his camera. In deciding to make his daughter his subject, Block isn’t a mere doting dad: She’s a genuinely captivating character, who in a series of exquisitely edited sequences evolves from an enchanting, dimpled child into a self-possessed young woman of serenely regal bearing. One moment she’s a babbling toddler in the back of Block’s car and in an instant she’s driving it, a wordless, graceful expression of the time-warp occupied by parents who can’t help but see the baby in the adults their children become.

As Lucy begins to prepare for college, along the way acquiring a serious boyfriend, Block begins to film her more obsessively, all the while observed by his preternaturally understanding wife, Marjorie. A wise, unflappable law professor, Marjorie greets her husband’s increasing anxiety over Lucy’s impending departure with frank equanimity, at one point asking whether his distress has less to do with missing Lucy than “what the rest of your life is going to look like.”

Of course, she’s right: As “The Kids Grow Up” takes its twists and turns throughout the year, it becomes more clearly evident that the film isn’t about Lucy at all but about confronting the larger looming issues of aging, mortality and the meaning of marital intimacy. As Block’s father says at one point, the hardest part of the empty nest is being “faced with your own life.” Personal without falling into solipsism, revealing without succumbing to exploitation, achingly sad, but suffused with tenderness, optimism and warmth, “The Kids Grow Up” exemplifies personal filmmaking at its most truthful and absorbing. It’s more than all right. It’s wonderful.

Unrated. At the Avalon. Contains nothing objectionable. 90 minutes.