Doctor Who is one of those TV series that you may not watch, but you probably know someone who does. And if you're not already a fan, it seems daunting to dive into a show that has a history going back more than 50 years.

That said, you don't need to watch every single episode of Doctor Who to get into the series — although once you're hooked, you might want to.

There are a few episodes, particularly among the newer ones that launched in 2005, which not only explain a lot about who the Doctor is and what he does, but also give you insight into understanding much of the rest of the show.

You can look at these essential episodes as springboards: places to start that will give you what you need to understand Doctor Who, just in time for the next season that begins on September 19.

Even better? You can watch all of these episodes now on Netflix.

"Rose" (Season 1, Episode 1)

There is no episode as important for understanding the concept of Doctor Who than the first episode of the new series: "Rose." Not only did this episode introduce Christopher Eccleston as the ninth Doctor, but it also gave us a little backstory on who and what the Doctor is, while also helping us understand the significance of the Doctor's companion. The episode even re-introduced the Autons, an alien race from the classic series. If you're going to begin anywhere with Doctor Who, "Rose" is the place to start.

"The Empty Child" / "The Doctor Dances" (Season 1, Episodes 9-10)

"The Empty Child and "The Doctor Dances" make up a two-part story that not only takes the Doctor back to World War II to face kids in gas masks asking "Are you my mummy?" but also introduces Captain Jack Harkness. This is important, because Jack returns in later episodes, in addition to becoming the head of Torchwood — which leads to the spin-off series of the same name. Finally, this episode gives us some insight into the burden the Doctor carries, particularly when he decides that this time, he can save everyone and that "everybody lives."

"The Parting of the Ways" (Season 1, Episode 13)

The concept of the Doctor's regeneration is a little confusing, particularly for new fans of the series. In this episode, we see the ninth Doctor regenerate and learn a little more about the process and why it's important to the series. This is also the first peek we get at one of the most popular Doctors of all time, David Tennant's 10th Doctor.

"Rise of the Cybermen" / "The Age of Steel" (Season 2, Episodes 6-7)

In this two-parter, we learn about the Cybermen — another classic Doctor Who alien species that gets explained well in these two episodes. They also explore the idea of alternate universes and the difficulties they pose for the Doctor.

"Smith and Jones" (Season 3, Episode 2)

The Doctor goes through companions almost like he probably goes through socks — so this episode introduces the Doctor's newest companion, Martha Jones, who is very different from his previous companion, Rose Tyler. This episode is a great way of understanding how the Doctor chooses companions and, in turn, how they choose to travel with him. It also reveals the sense of loss he feels once a companion is gone.

"Blink" (Season 3, Episode 11)

This is, by far, one of the best Doctor Who episodes of the new series. If any episode will get you hooked, it's this one. It features the Weeping Angels, which are stone statues that move when you turn your back on them, or when you blink — if that happens, they'll send you back through time. It's a standalone episode, so no previous knowledge of the series is necessary to understand it. It's also terrifying and highly entertaining.

"Utopia" / "Sound of Drums" / "Last of the Time Lords" (Season 3, Episodes 12-14)

This three-episode arc is a good standalone story that brings back the Doctor's greatest nemesis (and closest friend): The Master. If you want to know who The Master is and learn more about why he and The Doctor are enemies, this story arc explains it all. It's also one of Martha Jones' best stories, as she takes it upon herself to save the day.

"Silence in the Library" / "Forest of the Dead" (Season 4, Episodes 9-10)

In these episodes, the 10th Doctor first meets River Song, an important character in later episodes of the series (also recently announced for the upcoming season). This episode explains the strange "wibbly-wobbly timey-wimey" relationship the Doctor has with River, giving us a hint of how important she is to his future.

"The Eleventh Hour" (Season 5, Episode 1)

The 11th Doctor makes his first appearance in "The Eleventh Hour," with Matt Smith displaying all the quirks that come with regeneration, especially when everything changes, even simple things as what the Doctor likes to eat. This episode also introduces Karen Gillan's Amy Pond, who quickly became the favorite companion of many fans.

"The Wedding of River Song" (Season 6, Episode 13)

Remember River Song from "Silence of the Library" and "Forest of the Dead"? In this episode, we see her importance to the Doctor come full circle. This is also the episode in which the Doctor faces his impending death and concludes the story arc of the entire sixth season of the Doctor Who.

"Dark Water" / "Death in Heaven" (Season 7, Episodes 12-13)

If you're wanting to understand the new season of Doctor Who that premieres in a few weeks, these two episodes are required viewing. Not only do they give us a great introduction to the villainous and insane Missy (who will play a part in the new season), but these two episodes also bring back the Cybermen and set the stage for Season 9.

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