Human skin is the subject of a National Geographic special. NBC revives the '80s cop show Hunter in a TV movie. The History Channel takes its History of Britain series into its final hours. TV Land offers a countdown of the top 40 TV theme tunes. PBS renders a 90-minute salute to comedian Bob Newhart as he receives the Mark Twain Prize. William Hurt stars as convicted spy Robert Hanssen in a CBS miniseries. And the PBS series American Experience takes a two-part look at Jimmy Carter.

In CBS's four-hour two-night production, "Master Spy: The Robert Hanssen Story," Lawrence Schiller directs William Hurt as he plays the former FBI special agent responsible for one of the gravest breaches of security in American history.

The production, airing from 9 to 11 p.m. this Sunday and next, was filmed from a screenplay by novelist Norman Mailer and based on the research he and Schiller conducted over a nine- to 12- month period.

The miniseries comes at a time when interest in Hanssen remains high. Sentenced to life in prison earlier this year after selling secrets to the Russians off and on for 22 years, Hanssen was the subject of a recent program at Washington's new Spy Museum featuring author David Wise ("Spy: The Inside Story of How the FBI's Robert Hanssen Betrayed America").

What viewers will find unique to the miniseries, said Schiller, is its psychological profile of the man based on extensive interviews with friends, family members and former colleagues.

The picture that emerges is that of a man whose deeds stand in stark relief to his beliefs. From outward appearances, he was a dedicated agent committed to defeating enemies of the United States. He was a strict, conservative Catholic, committed to his wife and six children. Yet he sold information to the Russians, carried on an extensive, platonic relation with a strip-tease dancer, and passed nude photos he had taken of his wife, Bonnie, to his best friend.

"If you want to believe what Hanssen has told people," said Schiller, "he felt the Soviet Union was bankrupt by 1985 and that the course we were taking would put their finger on the nuclear trigger. By given them information, they would be less scared and not resort to nuclear war. Whether that's a self-serving statement or the truth, we'll never know."

The sexual content of the film, with some nudity in an early version of the work, will land the series a "mature audience" rating. Hanssen's sexual antics, which at times seem juvenile and at other times cruelly insensitive, go back to his adolescence, said Schiller. "When he was in high school and college he was the dork. He never got the girl," said Schiller. "When he marries a girl and has a sexual relationship, he can't stop talking about it."

Mary-Louise Parker plays his wife; Peter Boyle plays his father, Howard; Ron Silver plays his FBI supervisor; and Wayne Knight plays a fellow FBI analyst.

The drama was filmed in Hong Kong, Moscow, Hawaii, Toronto and the District.

--Michael E. Hill

NATIONAL GEOGRAPHIC: SKIN

Wednesday at 8 on PBS

This program explores how human skin originated, how it cools people and why it comes in different colors. There's also a chronicle of the far-reaching social implications of this amazing survival suit.

Computer-generated imagery includes brightly colored animations that illustrate the biology of skin, uncover connections between the human brain, nerves and skin, and show its many amazing features: how it prevents the body from boiling, for example, and how it repairs itself.

Anthropologist Nina Jablonski, an expert in human evolution and, in particular, how human skin has adapted over the ages, theorizes: "There are no races. There are simply people in different parts of the world with different attributes."

The film also follows photographer Spencer Tunick, who believes that skin is the ultimate art form and photographs groups of nude models in public spaces. Arrested five times, Tunick has successfully defended his right to express himself through his unconventional art all the way to the U.S. Supreme Court.

National Public Radio's Alex Chadwick narrates.

HUNTER: RETURN TO JUSTICE

Saturday at 9 on NBC

In this movie based on NBC's popular cop drama series (1984-91), Fred Dryer returns as Lt. Rick Hunter, who is left with a dead partner after a drug bust goes bad. A police investigation questions his integrity. Taking time off, Hunter visits his friend and former partner, Stepfanie Kramer as DeeDee McCall. Hunter then finds himself pressed into service when her fiance, a San Diego mayoral candidate, kills an intruder during a robbery--and unleashes a mysterious chain of events.

PRIME-TIME SEASON RETURNS

Futurama Sunday at 7 and The Simpsons at 8, both on Fox.