Tuvok is the unluckiest Vulcan in Starfleet. Unlike Spock, Saavik or Sarek, he has a name beginning with a T and unlike those first two, originally he couldn't cut it at Starfleet.

Forget graduating at the top of the class like Valeris. Tuvok couldn't cope with life at the Academy and aboard the USS Excelsior so he walked out. Fifty years later, he had a rethink and came back to complete his training. And then he was flung across the galaxy and stranded on USS Voyager.

He faced different pressures to those of Spock. In Tuvok's case his family pressured him into joining Starfleet where Spock's father was against his entry. And when he left, he didn't idle about - he went straight into studying for the Vulcan Kohlinar. That's an extreme course of mental training which Spock failed to complete. Unfortunately, Tuvok left that early, too.

These are all things you'd keep quiet about, and Tuvok did too. But he's also kept very quiet about his much more successful ventures. He was six years into the Kolinar and he was doing pretty well when he underwent Pon Farr. For a Vulcan, there is no better reason for leaving anything and the examiners are probably still holding his place open.

Once he went into Pon Farr, though, he mated with T'Pel and has now been married to her for over 70 years. They have four children and it was in raising them that Tuvok learned why his parents pressured him the way they did. Understanding that and rethinking his decisions, Tuvok chose to return to Starfleet Academy and pick up his studies as a very, very mature student. This time out he was much better and ended up becoming a teacher, too, at the Vulcan Institute of Defensive Arts.

In many ways his background means that he's vastly more experienced than Spock. Where Spock has to cope with his human side, Tuvok is 100% Vulcan - logical, analytical and in theory incapable of lying. In practice, he still managed to lie through his teeth and go undercover with the Maquis.

Tuvok is also the only character to have lived and worked in the Starfleet both of Captain Kirk's wild days and the more sober times of Picard, Sisko and Janeway. That's fitting because actor Tim Russ is the only one of Voyager's cast to have done the same.

Bizarrely, almost as if Russ knew something about the producers, they kept hiring him until they could get him a series regular spot. He was the second choice to be Geordi La Forge in The Next Generation, for instance, and he did manage to pop up as the Vulcan T'Kar in Deep Space Nine, as someone else entirely in The Next Generation's Starship Mine and as a tactician in Star Trek: Generations.

Key Tuvok episodes: Worst Case Scenario, Flashback, Meld