Viewers first met "Villanelle" (Jodie Comer) and "Eve Polastri" (Sandra Oh) when Killing Eve premiered in 2018.

But fans of spy and assassin literature may have known the characters beforehand, if they were familiar with the work of Luke Jennings. The British author is behind the series of novels that were the inspiration for Killing Eve and first contained the "Villanelle" and "Eve" characters. Here's what you need to know about the books.

Killing Eve: The book series that inspired the TV show

Author, critic, and journalist Luke Jennings wrote his first novels in the 1990s, some time before he would introduce the world to "Villanelle." After work in various genres, the British author began to release thriller Codename Villanelle, which was published as a series of four e-book novellas between 2014 and 2016.

The series introduced "Villanelle" and "Eve Polastri" as Killing Eve fans know them now. It traced the Russian assassin's origins and her work with "The Twelve," as well as the eventual investigation involving MI5 agent "Eve." Following Codename Villanelle, Jennings has released two sequels, Killing Eve: No Tomorrow (2019) and Killing Eve: Die For Me (2020).

Killing Eve: TV show vs. books - The differences

Whereas the TV series is "based on the Villanelle novels by Luke Jennings," the author's two sequels are noted to diverge from the direction of TV's Killing Eve. Whether or not the show will reconnect with the later novels remains unclear as it heads into season 4 and beyond.

There are also important differences between the TV series and novels, including:

  • More "Villanelle" and "Eve" face-to-face time on TV
  • Additional "Villanelle" backstory in the books
  • "Villanelle" is more ruthless and "Eve" is younger and British in the books
  • The character of "Carolyn" is a man in the novel series
  • Deaths, assassinations, and romances differ between TV and books

"The plot that suited the book is similar to what they used on TV, but it's not the same in all aspects," Jennings explained in a 2020 interview. "I think of the books as occupying the same imaginative universe as the TV series and featuring most of the same characters, but they're complementary," he added. "They're not the same."

To explore the origin of — and a new angle to — the TV show that many know and love, read Luke Jennings's Codename Villanelle and Killing Eve sequels today.

'MALCOLM IN THE MIDDLE', Erik Per Sullivan, Frankie Muniz, Justin Berfield, Season 1.

Test your knowledge

What part does "Holly Shumpert" play in 'The King of Queens'?

'Dark' Netflix Series Critical Reception

Positive response to German production

'Dark' Netflix Series' Critical Reception