Robert Culp and Bill Cosby could well be playing pals today, they're so warmly witty, bantering as they blast the bad guys into submission. As Culp astutely points out in DVD commentary on the show's pilot episode, they were pioneers in the "buddy" genre later to widen to movies from Butch Cassidy and the Sundance Kid to Lethal Weapon and TV shows from Starsky and Hutch to Miami Vice.

That means Culp and Cosby were co-equals, not hero and sidekick. The dual billing was rare enough in that star-driven time. But something else was unheard of -- Culp being white, Cosby being black, easy friends and expert espionage partners, in the civil rights era when Southern schools were still segregated and Congress was just passing the Voting Rights Act.

I Spy doesn't make a big deal about this. But it doesn't ignore it, either, which makes the show yet more amazing. Culp explains in that pilot commentary how the series was put together, and also how he ended up writing the pilot. Which wasted no time demonstrating the show's fresh approach. The two lead guest stars -- Ivan Dixon (Hogan's Heroes) and future double Emmy winner Cicely Tyson (The Autobiography of Miss Jane Pittman) -- were black, too, in a tale of an American Olympic idol who defected to "Red" China in the midst of the Cold War.

Culp pretty much hands Cosby the episode's central role, a complex portrayal of a Rhodes Scholar agent with conflicted feelings about trying to repatriate a "brother" who defected for cold hard cash. Cosby's Alexander Scott character, whose cover is coaching Culp's globetrotting tennis player Kelly Robinson, even gets the chance to speak Chinese and translate into Swahili (!), presenting his unimpeachable credentials in no time flat. No wonder Sidney Poitier's character two years later in the big screen's big-time race treatise Guess Who's Coming to Dinner? had to be a Nobel Prize candidate. Cos had already upped the ante for black men that white America could not deny.

He carried the same kind of controlled anger, too, as Culp notes in his commentary about Cosby's casting, another astonishing notion at the time considering he'd done only stand-up comedy to that point. Cosby would go on to win three consecutive best-actor drama Emmys, shutting out Culp, of course, who was as integral to the show's success as his pioneering partner. They shared an easygoing rapport and hip humor that lifted I Spy above TV's other derring-do secret agent sagas in the wake of the James Bond craze (niftily ribbed in pilot dialogue). Yet they were both clearly adults, as was their show, engaging issues and themes much more maturely realistic than the near-cartoon fantasy adventures of The Man From U.N.C.L.E. or The Wild Wild West.

Maybe that's why I Spy hasn't cultivated a cult like those shows, which cemented their fandom in the hearts of baby boomer kids. Culp and Cosby appealed to the head -- the mind -- and the adult mind at that. Despite the stars' banter, the overall tone is serious, and the pace measured (a bit too measured, perhaps, for today's tastes). Bad and good aren't always so clear-cut -- presaging the nuance that wouldn't truly blossom in TV drama till two decades later with the character-driven ensembles of the '80s.

But that means I Spy is still resonant, unlike its now-campy competitors. The character portraits remain gritty and poignant alongside that crisp buddy wit. And you can't beat the show's look, with exteriors filmed on location each season in such "exotic" locales (in this early jet era) as Hong Kong, Tokyo, Greece and Italy. Even good old Las Vegas, which makes for a nice little retro '60s time trip.

It's only moments like this that remind us we're not in the 2000s anymore.