The first episode of the British sci-fi series aired on November 23, 1963.

It’s a very important day in nerd history: the 48th anniversary of the debut of “Doctor Who.”

History

For the uninitiated, “Doctor Who” tells the story of the Doctor, a centuries-old Time Lord who travels around throughout space and time in a machine called the TARDIS, usually with a human companion, saving the universe from various enemies and dangers.

The original series ran from 1963 until 1989, then a movie was produced in 1996 and the series was rebooted in 2005. The new version, which currently stars Matt Smith as the Doctor, just wrapped its sixth season.

The Debut

The first episode, “An Unearthly Child,” starts with a pair of teachers in a high school worrying about one of their students, Susan Foreman, who is exceptionally brilliant in some areas but bizarrely misinformed in others. They follow her to her home, which leads them to a police phone box inside a junkyard. Upon stepping inside — which is bigger than the outside — we get our very first glimpse at the TARDIS and learn that it stands for “Time and Relative Dimension in Space.”

Very little is revealed about the Doctor, played by William Hartnell, in that first episode. He appears very different than later versions, however, seeming harsh when he speaks to his granddaughter Susan, and when he refuses to let the two teachers leave the TARDIS. It’s leaps and bounds from the more jovial current incarnation.

The half-hour episode ends with the TARDIS landing on a mysterious desert-like terrain, with an ominous shadow approaching.

The Doctor and Companions

The Doctor was not originally written to be a reincarnating character, but Hartnell’s health started to fade and the writers needed to devise a way to keep the show going after the actor left. So they wrote in the Time Lord’s ability to regenerate himself. He went through seven incarnations during the series’ original run, then the eighth version starred in the movie, and versions nine, ten and eleven have been featured in the reboot.

The longest-running Doctor so far is the fourth version, played by Tom Baker, who was on the show from 1974 through 1981. He may also be the most iconic, with his signature extra-long, multi-colored scarf.

Aside from years of goofy storylines and writing that combines interesting and sometimes scary science fiction with sharp wit, the rotating cast has helped the longevity of the series. It keeps it from falling prey to the whims of a single star, but it also keeps things fresh. There has been some kind of change-up almost every season of the new series. If the Doctor stays the same, then the companion changes. Since 2005 we’ve seen Rose, Martha, Donna and Amy come along in the TARDIS, sometimes also accompanied by friends, family or significant others from their own lives.

Fans tend to rally behind the different Doctors and companions, and having new ones every couple of years keeps it from going stale. And since each companion and each version of the Doctor has a unique personality, the dynamic of their relationship is constantly shifting. Their interactions can be as compelling — or sometimes more so — than the actual plot of an episode.

Monsters

There have been different versions of various enemies over the years, but some of the most popular are the Daleks and the Cybermen. The Daleks are the Doctor’s most feared enemy, and though they look like upside-down trash cans with plungers for arms, they are viciously lethal and practically indestructible, with their trademark cry of “exterminate.” The Cybermen are “upgraded” humans — they take a human brain, remove emotions, and put them in a metal suit. They are similarly lethal and indestructible.

Weeping Angels are a fan favorite, despite being a brand new enemy. They debuted in the 2007 episode “Blink,” and appear as stone angel statues if anyone is looking at them but can move and kill when no one is watching.

Watching the Show

For anyone wishing to start watching the show, the best place for an introduction is the premiere episode of the rebooted series. That debut, “Rose,” introduces the audience to the ninth Doctor, played by Christopher Eccleston, and his companion Rose Tyler, played by Billie Piper. Give it a chance, because the first episode is a little slow, but then it picks up.

There’s too much history and referencing back to start at any of the next few seasons — even when the Doctor regenerates into David Tennant‘s tenth version, he still has his relationship with Rose established — but another starting point is season five.

Tennant’s Doctor has regenerated into Smith’s eleventh, and we’re introduced to a new companion, Amy Pond, at the same time. There was also some shifting with the creative team, so the series had a small makeover. If all you want is to get caught up in time for the Christmas special, watching season five and six then moving backwards would work.

A word of warning: this is one of those shows that’s hard to be a casual fan of. People seem to either not be able to get into it, or become at least mildly obsessed. If you sit down to watch one episode, you may end up watching four in a row. There’s a lot of truth to this cartoon:

But with a holiday weekend, curling up with your Netflix account to watch “Doctor Who” could be a great way to avoid actually spending time with your family. In the mean time, watch a clip from the series’ 1963 premiere episode below:

[Cartoon via Art 'n' Stuff]