An autumnal glow suffuses “56 Up,” the latest installment of the Granada Television documentary series that began in 1964 by introducing fourteen British seven-year olds from different backgrounds and has revisited them every seven years since. (Actually, one of the subjects quickly dropped out, and another followed suit after “28 Up” but returns for this installment.) Michael Apted has been with the project since the start, first as a staff member and then as director, and it’s his voice that one hears asking the gently probing offscreen questions of the now fifty-six-year old subjects.

As always, for those who have been watching these films for years (or, in some cases decades), it’s fascinating to catch up with these men and women—rather like going to a reunion and listening to old acquaintances bring us up to date on what’s been happening to them. Just seeing them again—most of them paunchier and with far less hair—brings smiles of recognition, particularly because Apted and editor Kim Horton are careful to shuffle in plenty of footage from previous installments. Some, of course, are more striking than others. Two are the subjects whose lives have taken particularly sad turns. One is Jackie Bassett, whose financial situation has grown precarious because arthritis has made it virtually impossible to find a job and government cutbacks are threatening her ability to survive even as family problems mount. The other is, of course, Neil Hughes, whose childhood ebullience dissipated as he became a university dropout, wandering the roads homeless and jobless in earlier episodes. As in “49 Up,” he’s recouped somewhat—finding a place as a local council member in the rustic north and as a lay minister as well. But he remains a poignant, somewhat pathetic figure living on the emotional (and practical) edge.

Most of the others have achieved much greater security, though for some—like the three upper-class subjects, all of whom exhibit a special degree of caution in expressing themselves—doing so wasn’t much of a struggle. And most seem reasonably content, many particularly because of their long, strong marriages and the success of their children (who get far more screen time this time around, with only one identified as having run into major personal difficulties). It’s especially interesting to encounter Peter Davies again—who dropped out of the series twenty-eight years ago because, as a young teacher, he made some mild anti-Thatcher observations that led to verbal attacks against him and now returns, largely because—as he unabashedly admits—he wants to promote his country-Western band. And of course voluble Cockney Tony Walker, the wannabe jockey who instead became a cabbie, always makes a strong impression, revisiting his childhood neighborhood and making a few remarks about its present population that lead Apted to raise the issue of racism—a charge Walker utterly rejects. Like others of the lower-class subjects, he also reflects the impact of the recent world economic downturn on the lifestyle of ordinary people. All the others have their moments too, though mostly at lower volume.

The “Up” series is quite simply one of the great documentary projects in the history of cinema, an engrossing sociological experiment on film; and though this mostly mellow installment isn’t as revelatory as some earlier ones, it’s still a remarkable document. For those who have been following the series, this eighth installment will be a no-brainer. But Apted has made it accessible to newcomers as well, by presenting it in what amount to individual segments on the thirteen subjects, seamlessly melding footage from previous “episodes” with newly-shot material to provide virtual mini-biographies.

And if you are coming to the “Up” films for the first time, you’ll probably be drawn to check out the seven preceding installments. Happily, you’ll find them on DVD. A marathon would not be out of order.