With so many great science fiction novels available, readers really are spoiled for choice. Some involve artificial intelligence. Others are grand space-operas. And some have even been banned from public distribution for dubious reasons.

Every geek has to start somewhere. If you want to build a library of must-have sci-fi novels and novellas, here are the best science fiction books of all time—redefining the genre, gaining cult status, and being adapted for film, television, and radio.

1. The Time Machine

This is the go-to book about traversing the fourth dimension. Science fiction legend H.G. Wells definitively presents the concept and term for a vehicle that can physically breach the fabric of space-time to deliver a person into another time.

The story involves an unnamed Time Traveler going into the far future and is wrought with social and political metaphors. The Earth is on the brink of solar annihilation, and society has devolved into two breeds: the peaceful Eloi; and the violent, animalistic Morlocks.

This book is the source of a number of science fiction story devices, including our dying sun and the conflicting classes of humanity.

2. The War of the Worlds

Just as Wells codified time travel, he also begat the alien invasion story with The War of the Worlds. It’s a tale of survival during an alien incursion, in a thinly-veiled commentary on British colonialism.

You’ll find many familiar sci-fi tropes here: A technologically superior alien force; humans as cattle; walking robot ships; and subpar human resistance. It’s been adapted many times, notably the 1938 radio broadcast, narrated by Orson Welles.

3. I, Robot

Isaac Asimov devised the Three Laws of Robotics, governing what machines can and cannot do—notably, that they can’t harm humans or themselves, and must carry out instructions given by humans.

These developed in the short stories from his 1950 collection, I, Robot. They’re quantified in “Runaround,” a tense tale in which the conflict between the laws cause deadly confusion in a positronic brain.

Are the Three Laws applicable to real-world artificial intelligence? The fact they’ve entered scientific discourse is testament to the importance of Asimov’s works.

These laws also form the basis for some of your favorite films and TV series about robots and robotics, including Humans (2015-18), Big Hero 6 (2014), and Westworld (both Michael Crichton’s 1973 movie and the HBO show it inspired).

4. 2001: A Space Odyssey

You’ll surely have heard of (if not seen) Stanley Kubrick’s 2001: A Space Odyssey. Unlike the other novels on this list, Arthur C. Clarke’s dense novel was written concurrently with its film adaptation, but certainly has a charm of its own.

Unlike the film, the book is hard science, so makes for an engaging read. It also explains the movie’s plot more clearly, especially regarding the monoliths and their relation to humanity.

5. Do Androids Dream of Electric Sheep?

Philip K. Dick’s meditation on artificial life inspired the classic sci-fi noir film, Blade Runner. However, if you were to compare them, you’d see a substantial gulf.

The book focuses more on identity and emotion than the mechanics of electronic lifeforms (including the eponymous electric sheep). Importantly, it asks whether something created can have the same relevance as something natural.

6. The Hitchhiker’s Guide to the Galaxy

Douglas Adams’ radio-play-turned-novel The Hitchhiker’s Guide to Changing Stories Across Mediums Mediums have different strengths and weaknesses, and adapting a text from one to another sometimes calls for substantial changes. No one understood this better than legendary science fiction author Douglas Adams. Read More is pure lunacy—which is why it should ideally be read in once sitting. It’s less a novel and more a series of stories strung together into one big continuity.

The Earth is immediately destroyed, leaving Arthur Dent, armed only with a towel and his dressing gown, to traverse the universe with his friend, Ford Prefect. It’s absurd and hilarious. Douglas Adams wrote it without having a clear structure, meaning you’re on as unexpected an adventure as Dent.

7. Neuromancer

In William Gibson’s Neuromancer, human minds interface with the Matrix, an interconnected cyber network that will seem very familiar to readers. Chase, the protagonist, has been rendered incapable of jacking into the Matrix after a past crime, and he’ll do anything to regain this ability.

The book left a considerable mark on the genre. Some have speculated that the Matrix in Neuromancer became the blueprint for the modern internet, in a metaphorical sense if not a strictly-technical one.

It is also filled with a number of great descriptive phrases, including a killer opening line, “The sky above the port was the color of television, tuned to a dead channel.”

8. Fahrenheit 451

If you’re looking for great opening lines, Fahrenheit 451 has one of the best: “It was a pleasure to burn.”

Sci-fi isn’t always about spaceships and technological marvels. Ray Bradbury’s seminal novel presents a dystopian world in which what we now call “political correctness” has reached the nth degree. The population is scared of new ideas, and so books are destroyed. Our unlikely main character is Guy Montag, a fireman—that is, someone in charge of burning books.

It’s a startling take on what our world might become if we shy away from deviations from the norm. It’s utterly chilling but strangely life-affirming too, and will stay with you long after you’ve turned that final page.

9. Snow Crash

In this 1992 book, humans interact on the “Metaverse,” a next-generation internet integrating virtual reality; this technology is sure to remind you of VR headsets such as the Oculus Rift. A mysterious virus called Snow Crash has started infiltrating Metaverse users’ brains, and it’s up to hacker Hiro to stop it.

Originally conceived as a graphic novel, Snow Crash is an action-packed thriller; it might come as a surprise, then, to learn that the plot derives from Sumerian mythology.

If you’ve referred to an online persona as an “avatar”, you alluded to Neal Stephenson’s Snow Crash. Similarly, the novel inspired both Google Earth and Second Life. The effect this underappreciated book has had on modern culture is massive.

10. Ready Player One

Ready Player One is as much a nostalgia trip as it is a novel. Ernest Cline’s tale posits that, by 2045, a massively multiplayer online game (MMO) will have largely replaced face-to-face communication.

The protagonist, Wade Watts, is obsessed with finding a treasure hidden within the game that requires extensive knowledge of an esoteric subject: 1980s pop culture.

Ready Player One revels in niche references, so if you have even a passing interest in video game trivia, this book definitely deserves a place on your bookshelf. It’s an interesting examination of vintage technology and the reverence some people have for it.

1980s nostalgia is particularly popular right now, so here’s everything you need to know about retro gaming Everything You Need to Know About Retro Gaming The Really Useful Podcast breaks down the retro gaming resurgence: why has it happened, and what’s the best way to play old games? Read More .

Are These the Best Sci-Fi Books Ever Written?

Of course, this list is just the tip of the iceberg, but acts as a solid foundation to any science fiction collection. From these essential titles, you can go on to explore the realms of J.R.R. Tolkien, the dystopias of George Orwell, and the whimsies of Terry Pratchett.

And if you’re looking to expand your library beyond solely sci-fi novels, keep up to date with our list of the best books to read right now The 20 Best Books to Read in 2019 Here are the best books to read in 2019, focusing on standout books from a handful of categories as well as best-selling books. Read More .