There is an enormous volume of information available about Doctor Who, both online and in print. This website alone offers millions of words on the topic, including summaries of each story, details about the production of every season, and more.

Unfortunately for newcomers to Doctor Who, many sources assume a basic familiarity with the programme. If you've never heard of “Sylvester McCoy”, or if the date “November 23rd, 1963” means nothing to you, you may find yourself baffled by strange names and terms. So what do you do if you've only seen a handful of episodes -- or perhaps none at all -- and want to learn more? Well, you've come to the right place.

These 13 questions and answers should tell you everything you need to know to gain a basic understanding of Doctor Who and its history.

Doctor Who is a television show. It has been aired by the British Broadcasting Corporation (BBC) in the United Kingdom since November 1963, albeit not continuously. Because it's about time travel, Doctor Who is usually considered to be a science-fiction series. However, individual stories run the gamut from action-adventure to gothic horror to dark comedy.

Doctor Who is about an alien time traveller known as the Doctor (“Doctor Who” is very rarely used as the name of the character -- typically only in the end credits). The Doctor is a member of a race of beings called the Time Lords, from the planet Gallifrey. Most Time Lords obey a strict policy of non-interference in the events of the universe, but the Doctor is a renegade, willfully intervening in history in order to fight evil and aid the oppressed.

The Time Lords use a time machine called a TARDIS (which stands for Time And Relative Dimension In Space). The Doctor's TARDIS is a very old model which doesn't always work properly. A TARDIS is dimensionally transcendental -- which is a fancy way of saying that it's bigger on the inside than the outside. The interior, which comprises a main control room and a plethora of other rooms and corridors, exists in its own dimension. The exterior of a TARDIS, on the other hand, is usually quite small. By virtue of the chameleon circuit, the outer shell is supposed to transform in a way that will blend seamlessly with its surroundings -- appearing, for example, as a Corinthian column upon landing in Ancient Greece. However, on a trip to 1963 England, the chameleon circuit in the Doctor's TARDIS broke down and has never been successfully repaired. As a result, the Doctor's TARDIS is now permanently stuck in the shape of a blue police box. The Doctor's TARDIS is pictured on the right (click on the image for a larger view).

The Doctor was originally played by an actor named William Hartnell. However, by 1966, Hartnell's health was failing and it became obvious that he could not continue on as the star of Doctor Who. It was decided to cast a younger actor the role. To explain the Doctor's altered appearance, a concept was invented which eventually became known as regeneration: when afflicted by very old age or a mortal wound, a Time Lord's body undergoes a transformation which generates a new physical form and a modified personality. This is why you will often see references to, for example, the “Fourth Doctor” -- referring to the fourth incarnation of the Doctor to have served as the programme's protagonist.

This is a bit tricky to answer, both because of complexities which have arisen in the chronology of the Doctor's own life, and because there have many different spin-offs of Doctor Who, which have sometimes used actors/Doctors different from those who appeared in the televised programme (see Question 12, below). In principle, though, it is generally agreed that there are fifteen “official” Doctors: William Hartnell, Patrick Troughton, Jon Pertwee, Tom Baker, Peter Davison, Colin Baker, Sylvester McCoy, Paul McGann, Christopher Eccleston, David Tennant, Matt Smith, Peter Capaldi, Jodie Whittaker, David Tennant again, and Ncuti Gatwa. The Doctors are pictured below, in order from left to right (click on the image for a larger view). In addition, John Hurt portrayed an incarnation who fought during a terrible battle called the Time War, and who refused to think of himself as “the Doctor” due to the awful decisions he was forced to make. Jo Martin appeared as a version of the Doctor who predated the “First” Doctor, but whose existence was wiped from the Doctor's memory.

Not usually, no. Whether by accident or by design, the Doctor has a habit of picking up travelling companions (sometimes referred to as assistants) who participate in various adventures before they eventually part company. More often than not, the Doctor's companions have been young people from modern-day Earth, but others have come from Earth's past and future, and from other planets. There have been more than thirty companions over the year; the precise number is impossible to determine, as it's not always obvious whether a character officially “counts” as a companion. A few of them are pictured below (click on the image for a larger view).

The original Doctor Who series ran for twenty-six seasons of various lengths -- encompassing more than one hundred and fifty stories and over five hundred episodes -- between November 1963 and December 1989. In November 1993, a two-part made-for-charity mini-adventure aired, reuniting many past castmembers to celebrate Doctor Who's thirtieth anniversary. In May 1996, an original TV movie aired on both the BBC and the FOX network in North America; it was intended to lead to a new ongoing series, but this did not come to pass. In September 2003, however, the BBC announced that they were developing a new Doctor Who series, picking up where the original left off. It premiered in March 2005 and is still running, although the episodes which have aired since 2023 are sometimes considered to be a separate programme because they have been made under a co-production agreement between the BBC and Bad Wolf Ltd.

During its original run, most Doctor Who stories (also called serials or adventures) were made up of a number of individual episodes. These episodes were usually about twenty-five minutes in length, though some were longer. A cliffhanger ended every episode, and each episode usually started with a reprise of the previous installment. While some stories ran for eight or more episodes, and others for just a single episode, most were either four or six episodes long. The new series, on the other hand, is mostly comprised of standalone forty-five minute episodes, with occasional multi-part stories. Doctor Who serials from the Sixties were all in black and white; episodes from 1970 onwards have been transmitted in colour. Doctor Who was broadcast in high definition starting in 2009.

No, although some enemies have appeared more than once. Amongst the Doctor's most famous nemeses are the Master (an evil Time Lord, several incarnation of whom have faced the Doctor), the Daleks (metal-cased mutants famous for their “Exterminate!” battle cry), the implacable Cybermen, the reptilian Ice Warriors, the warlike Sontarans, the ferocious Yeti, the sinister Weeping Angels, and more. Some members of the Doctor's rogues' gallery are pictured below (click on the image for a larger view).

Doctor Who is broadcast on BBC One in the United Kingdom, and new episodes are available on the Disney+ streaming service outside the United Kingdom and Ireland. Most Doctor Who adventures are also available on DVD, with an increasing number being released on Blu-ray.

Sadly, yes. During the Sixties and Seventies, before home video recorders became popular, the BBC felt that they had effectively exhausted all of the commercial possibilities for early Doctor Who episodes. Because storing and maintaining the old tapes was becoming prohibitively expensive, the BBC decided to initiate a process of destroying some episodes -- this didn't just apply to Doctor Who, but virtually the entire BBC back catalogue. There was no real pattern to the purge but, by the time it was halted, dozens of episodes dating from the start of the series to the mid-Seventies were no longer held in the BBC Archives. Luckily, many have since been recovered. Nonetheless, just under a hundred episodes remain “lost”. Sometimes, entire serials have been destroyed; in other instances, just one installment is missing. The search continues for these “lost” stories, but the likelihood that they will all be found is remote. Fortunately, the soundtracks to all the “lost” episodes exist; they have been made commercially available, and have also formed the basis for animated reconstructions of certain missing episodes on DVD/Blu-ray.

Most certainly. Doctor Who has been adapted in the form of novels, comic strips, movies, audio plays, stage plays, and more. Some of them feature Doctors, companions and villains from the television series, while others introduce entirely new characters. A couple of Doctor Who feature films from the Sixties featured a human “Dr Who”. An Eighties comic strip gave the Sixth Doctor a talking penguin for a companion. A comedy charity special broadcast in 1999 featured celebrities like Rowan Atkinson and Hugh Grant as future Doctors! In 1981, a pilot episode was broadcast for a proposed spin-off series called K·9 And Company, featuring the Doctor's robot dog, K·9. In the twenty-first century, Doctor Who spawned two long-running television series: Torchwood (2006-2011), starring former companion Jack Harkness as the leader of a group which investigates alien phenomena on modern-day Earth, and The Sarah Jane Adventures (2007-2011), in which another ex-companion -- reporter Sarah Jane Smith -- explores the unknown with a group of young friends. More recently, Class (2016) chronicled the efforts of a small group of students at Coal Hill Academy to protect the Earth from extraterrestrial threats.

With hundreds of episodes to choose from, getting into Doctor Who can be a little intimidating. But the truth is that most episodes are pretty self-contained -- especially if you're armed with the information in this Beginner's Guide! Still, there are some stories that are particularly good jumping-on points. The debut of just about any Doctor can be a good choice: you could start with the very first episode (1963's 100,000 BC), or the first colour episode (1970's Spearhead From Space), or the first episode of the longest-serving Doctor (1974's Robot). If you're wary of sampling television from the Sixties, Seventies and Eighties, you could start with the first episode of the current century (2005's Rose) or the first episode of the last decade (2010's The Eleventh Hour). These days, the best place for a Doctor Who newcomer to start is probably the first episode to focus on the current Doctor (2023's The Church On Ruby Road) which was designed specifically to appeal to new viewers. But you could always just try one of the best-regarded stories from a Doctor of your choice. Click on an image below to check out a recommendation. Have fun!