Matthew Weiner, the creator of "Mad Men," was nearly a year old on June 1, 1966, which, it turns out, was Don Draper's 40th birthday. Draper's birthday is celebrated in the first episode of the series' fifth season.

The one-year-old aspect isn't a trivial detail; it's important if we're to understand the episode and evidently the rest of the season. A key element of "A Little Kiss," the double episode that was broadcast in the United States this week on AMC and is airing here this Saturday on HOT3, is babies and children.

Appearing in the episode are Don's (Jon Hamm ) three children, who are filmed in Draper's spacious and stylish New York apartment. Also appearing are new representatives of the early '60s (and late '50s ) generation - Joan's baby, who Joan (Christina Hendricks ) is raising with her mother's help, given her husband's absence. There's also Pete and Trudy's baby girl. We no longer see Trudy, but we hear Pete complain about what happened to her after she gave birth.

There's also an African-American child, who is brought with his mother and her demonstrating girlfriends to the New York office, which is filled with white workers. All these members of the new generation will be growing up in a United States undergoing major changes, changes that for now are being expressed in pencil skirts that are shrinking into miniskirts.

These babies and children will soon be in the middle of the revolutions of the '60s and '70s - the women's liberation movement and the civil rights movement. As adults they'll write about the employees' lives at Sterling Cooper Draper Pryce, or watch them.

Megan's turn to shine

Another new wrinkle concerns Megan (Jessica Pare ), the secretary who at the end of last season received a surprising marriage proposal from Don. So now she's the new Mrs. Draper.

This stunning, long-legged young woman is French-Canadian. She brings to Don's office and life different customs and a slightly naive air. She complains to Peggy (Elisabeth Moss ) that she doesn't understand "their" cynicism (That of the firm's employees? Of the ad execs? Of Americans in general? ) But not everyone understands her. Megan, in the role of the outsider, will apparently be one of this season's more interesting characters.

During the four seasons and six years depicted in the series, there has been a gradual change in the world of these New York ad men and their families. The gray suits and figure-hugging skirts have been supplanted by colorful, see-through, flowing materials with prints, checks and stripes. The women's hairdos have unraveled; now their hair jumps about in ear-length bobs.

At the office they still smoke, drink and sexually harass the women, but differently. Pete lets Roger know he shouldn't sexually abuse his secretary; later on, he asks Roger not to smoke. Perhaps this reflects the charged relationship between the two partners more than the greater changes afoot in society, but maybe not.

The change takes place gradually, at a deliberate pace characteristic of this dazzling period series (which, based on the season premiere, has lost none of its intricate complexity ). We witness the slow transition with all its nuances.

Although Weiner was careful not to reveal any details about the new episode before it was aired, it doesn't contain any major event (the only surprise, perhaps, is the absence of a certain female character, and this comes as no surprise if you've been following the behind-the-scenes chatter ). Changes, like the episode's story line, like the entire series, are prepared, as usual, at a low simmer. It's a delicacy with many layers and tastes, not all them obvious at first bite.

As meticulous as ever

The opening episode of the fifth season of Mad Men - a series that has won a pile of awards - is meticulous about the minutest details, which form a full, rich world. The episode, which set viewer records for the series, contains various scraps of conversation, some more beautiful (especially that between Lane and Joan ) and some less beautiful (such as Pete's friend on the train, explaining how to be absent from home as much as possible ).

There are work-world tactics (running want ads as a stratagem to fool competitors ) that lead to unintended and/or breakthrough developments. We also see Don's suspiciously good mood, even humor, mainly due to the murky relationship between Roger and Pete.

The high point of the episode is Dan's surprise party. (Did I spoil it for you? Never mind. Roger Sterling spoiled it for Don, too. ) At the party, Megan sings a song in French - "Zou Bisou Bisou" about a small kiss.

To Israeli ears, the seductive song, accompanied by a sexy dance, may seem childish, but it has a strong Israeli connection. A version of the song was recorded by the Israeli singer Maya Casabianca and made it into the French song festival in September 1961. (The song "The Look of Love" by Dusty Springfield was supposed to be on the soundtrack, but it was dropped when it turned out it came out in 1967.

Don listens to the song - given him as a birthday present by his young wife - with mixed feelings. Generally, he's not fond of being reminded of the passage of time.