You don't need to have seen the previous episodes of Michael Apted's remarkable documentary series 7 Up to appreciate its latest installment, 49 Up, which airs in two parts Sunday and Monday at 10 p.m. on YES Docu. Over the last two months, the cable documentary channel has broadcast each of the series' first six episodes, which charted the lives of a group of English boys and girls as they moved through adolescence, early adulthood and, now, middle age. One of the earliest experiments in reality TV - though no one would have known to call it that when it started - the series has checked in on group members every seven years since they were seven-years-old, and caught up with them most recently when they had reached 49. Though it's a unique pleasure to watch 7 Up participants change and age over the course of the first six installments, viewers will draw immense pleasure from 49 Up even if they haven't seen earlier episodes. To accommodate newcomers to the series, producers incorporate old footage into the latest chapter to explain who each participant is and how his or her life has developed over the past 42 years. As is explained early on, a group of children "from startlingly different backgrounds" were selected back in the early Sixties to test the series' central hypothesis: "Give me a child of 7, and I will give you the man." Based on the those featured in the series, it appears that, for better or worse, a person's life path can only loosely be connected to his or her early childhood experiences. As black and white footage from 7 Up recalls, the participants were fearlessly honest and uniformly charming at age 7, with one brown-haired boy reflecting on the topic of girlfriends and commenting, "I've got one, but I don't think much of her." Similarly comic is the threesome of haughty private school boys who are asked to comment on The Beatles - major stars when the series first aired. "I just loathe their haircuts," says John, whose impossibly posh accent seems to foreshadow his priggish later persona as an ambitious barrister and preserver of his "old family's" good name. More often, however, life has held surprises for series participants. Some of the twists are welcome: it's unexpectedly moving to see that Tony, who comes from an extremely limited background, has overcome his deprived childhood and become sufficiently wealthy to buy a vacation home in Spain. Other lives haven't been as straightforwardly successful. Nick, once an energetic seven-year-old who said he'd like to turn the world into a diamond, has endured a divorce and the frustration of years of scientific research that bore no results. Neil, perhaps the brightest-eyed seven-year-old of the bunch, spent years in homelessness and, it appears, addicted to hard drugs. But perhaps the most impressive aspect of 49 Up is that, for viewers at least, the outcomes of individual lives aren't nearly so compelling as the portraits drawn of participants over the course of decades. While each of the 49-year-olds have experienced a distinctly personal combination of success and failure, none is a societal outlier: none have become rock stars, heads of state or serial killers. Their relative ordinariness - such a rare quality on television - only makes their stories more interesting and relevant, with some of the original 7-year-olds even having opted not to continue their participation on the series. Of the majority who remain, there's poignancy - and occasionally pain - in watching cast members describe their experiences and try to draw lessons from their triumphs and hardships. By 49, nearly all the participants have achieved a fairly healthy sense of perspective, even as they joke about receding hairlines and sarcastic children. Some have made peace with past mistakes, while others continue to struggle with the insecurities of youth, like the man who referred to himself at 7 as "illegitimate" and four decades later remains unhappy about his fatherless childhood. Handpicked from an array of socioeconomic, educational and geographic backgrounds, the participants are to some extent a reflection of England in the years since 7 Up first aired in 1964. As they approach the half-century mark, however, even the politically-minded among them refrain from making sweeping generalizations about their society and its changing values. Instead, cast members are given the chance to reflect on their lives, free from heavy-handed editing and the obvious agenda of ratings-obsessed producers. The series' subjects are treated in a manner that's refreshingly honest and non-voyeuristic. May they live to film 120 Up.

'7 Up' at 49

New installment of documentary charting lives of participants since the age of seven.