The first series of QI, which was based around the letter 'A', made its debut on BBC Two in September 2003. The series answered 'an avalanche of A's', with the panellists being asked about Adams, Alans, Andersons, aquatic animals, astronomy and the antidotes of QI's patron saint - Pliny the Elder.
Following the success of the first series, QI came back in October 2004 for its 'B' series. The episodes got the panellists to bone up on 'B' byways, beetles, birds, bees, beavers, bombs, blue and boiling points.
The crazy canyons of the land of 'C' were what it was all about in the third series. First broadcast in 2005, these episodes contain conundrums on cartography, campanology, cockneys, clowns, China, chickens, Chelmsford and custard.
The 2006 series invited viewers to delight in the delicious 'D' diner and intake a delivery of drink, dogs, danger, death, differences, denial and deprivation. This fourth series also featured QI's first Halloween and Children in Need specials.
The fifth series aimed to exterminate the end of 'E' ignorance; engaging with electricity, eating, England, Europe, empires, entertainment and elephants in the process. All the episodes in this series had an 'Elephant in the Room' bonus. Panellists could score 10 points if they spot a reference to an elephant in any of the questions. Series E also saw the introduction of the 'QI Quickie' - originally meant to be a vodcast, each one contains some unbroadcast material.
Here is our guide to Series F of QI, the first series of the show to be broadcast on BBC One. It was also the first series to be given a longer 45 minute extended repeat on BBC Two on Saturday nights (titled QI XL).
The seventh series of QI was the first to be extended to 16 episodes long. It covered everything interesting beginning with 'G' - including geography, geometry, genius and Germany. This was the first series to have some episodes broadcast transmitted before the 9pm watershed, and also the first series to feature an episode with more than three guests.
Our guide to the eighth series. The show hovers over "H" subjects, including happiness, holidays, history, hoaxes, horses and humanity. This series saw QI broadcast its hundredth episode and the show's inventor, John Lloyd, guest on the panel for the first time.
The ninth series includes everything interesting beginning with 'I', including idleness, illness, insects, inventions, intelligence and injustice. This series of QI saw the series return to its original home on BBC Two.
QI goes into jubilant double figures (numerically speaking) with its tenth series, jesting over subjects starting with 'J'... such as jungles, jeopardy, journalism, jobs, justice and journeys. This 16-part series features 13 panellists making their debuts, including two from the southern hemisphere who have never appeared on British TV before. This series also includes the first episode in which all three guests are women.
The 13th series of the show, recorded in Spring 2015, sees the programme reach the half way mark in its plan to cover the whole alphabet.