The straight out of a first-grade primer address of the title tells much more than you'd expect about 51 Birch Street, a family-history documentary. In several respects this is a story about why seemingly normal families never are, and about the difficulties American children of the 1950s have in accepting their parents as more than progenitors. Filmmaker Doug Block set out originally in the early 2000s to explore the apparent success of his parents' 54-year marriage, an undertaking that itself bespeaks a certain myopia and that reminded me of a passage in Iris Murdoch's The Sea, the Sea: "A marriage is so hideously private. Whoever illicitly draws back that curtain may well be stricken, and in some way that he can least foresee, by an avenging deity. Some horrible and quite unexpected revelation could persecute the miscreant henceforth forever with an almost obscene haunting."

The first scenes are mostly banter with his mother, Mina, to whom Block always felt closer than to his father, Mike. Shortly after the project began, Mina died suddenly, the shock of her loss amplified by Mike's announcement of plans to marry his one-time secretary, Kitty, and move with her to Florida. 51 Birch Street begins as a portrait of assumed permanence; it becomes instead an inquiry into what a good marriage is and, inadvertently, a glimpse at the particular frustrations of the generation that produced the baby boom.

Block focuses primarily on the move out of the Birch Street house. Among the boxes, Block finds the daily journals his mother kept, spanning some 35 years. He somewhat disingenuously considers not reading his mother's confessions, though the fact that they were typed seemed an open invitation to posterity. There is, of course, never any question that he will do so since they provide the bit of weight and drama in this otherwise rather slight story. Eventually, Block gets a blessing of sorts from his mother's best friend who, milking the opportunity of his question for every drop of drama, finally concludes that Mina would be "delighted" to think her son finally knew her as a person.

Using earlier footage of his family; snapshots; interviews with siblings and other family members, a therapist specialist on father-son relationships, and a young rabbi, Block attempts to come to terms with his parents as real people rather than figureheads. The just-folks theme is echoed in the filmmaking itself, which feels like a well-shot home-movie, decently edited, but soundtracked with something like game-show-theme outtakes. Though the film runs only 88 minutes, there are times when the move out of the house seems interminable, the packing almost in real time.

True to his generation, Block has a belief in — and insistence on — a rational explanation for behavior, especially of people he had trouble seeing as more substantial than solely Mom and Dad. Though World War II topsy-turvied their lives, the illusion many members of the postwar generation tried to live up to was of rectitude, safety, and always knowing more than their children. The Blocks were no exception. Describing her profound astonishment at hearing her father tell her once "I don't know," Block's sister tags a general boomer credulity, an actual faith that father really did know best — and a huge reluctance to let this security blanket go.

Whatever their freedoms during the war years, women were subsequently expected to retreat into the nuturing role of helpmeet. As Mina notes in one exchange, among her peers not to marry meant "you were dead," though from her diaries it's clear that wedlock was certainly a kind of dead end. Stymied by three children in four years and life in the suburbs, the former urbanite eventually explored various aspects of the 1960s human potential movement in ways both public and private. Her diaries revealed that, in a supposedly fortressed marriage, Mina was something of a perennial loose canon. Though she acted on few of her desires, there were enough real escapades to put Mike's seemingly insensitive rush to marry in perspective.

In some ways, 51 Birch Street falls prey to the annoying habit of some fictional movies to be agog about the behavior that can and naturally does go on behind the well-kept hedges and lawns of suburbia. Ultimately, Block seeks to make a connection with his father; to get, in effect, a kind of blessing. Unused to expressing his feelings, Mike finally wishes for his son to be reasonably happy. For a generation ginned up by Disney, Lucy, and the Beaver, the idea that Mom and Dad are flawed human beings with complicated histories and real feelings can be hard to accept. Of historical interest as a limited testimony to the insulated world many baby boomers enjoyed, 51 Birch Street is a peep at one man's slow acceptance of the realities that underlie what's termed a good marriage — or a happy home.