Are you a hoopy frood who really knows where her towel is? Then you probably already know that Sunday marks 35 years to the day since legendary comedy/sci-fi author Douglas Adams published the novel based on his radio show The Hitchhiker’s Guide to the Galaxy, first in a trilogy of five books. Yeah, a trilogy of five — Adams was a weird dude!

The Hitchhiker’s Guide follows the story of a hapless human called Arthur Dent, who is saved from Earth’s destruction by aliens with just seconds to spare by his good friend Ford Prefect. Prefect, who Dent at first believes to be human, actually turns out to be an alien working for something called the Hitchhiker’s Guide to the Galaxy — sort of a combination travel guide/Wikipedia for intergalactic travelers roaming about the universe by grabbing rides on passing spacecraft.

Dent and Prefect wind up on a ship stolen by President of the Galaxy Zaphod Beeblebrox. Along with another human runaway and a depressed robot, the crew find themselves in a serious of perilous adventures one after the other and it’s all good fun with a great story that holds up in its own right while also poking a lot of fun at the generally very serious science-fiction genre.

Anyway. In celebration of Hitchhiker’s 35th birthday, here are 35 things you learn from reading the Hitchhiker’s Guide to the Galaxy “trilogy”:

1. If you’re ever stuck on a question, you know the answer is, of course, just “42.”

2. Forget “Keep Calm and Carry On.” The book teaches this motto: Don’t Panic, written in very friendly letters on the front of the actual Hitchhiker’s Guide.

3. You learn to always know where your towel is, because that thing can save your neck in more ways that you can count.

4. Dolphins are smarter than humans — but they’re still thankful for all that fish.

5. Earth, despite its nuclear weapons, war, bacteria and so on, is really just Mostly Harmless.

6. The secret to understanding all the universe’s languages is putting a tiny creature in your ear called a Babel Fish — and you also know that’s where the online translation service got its name.

7. When you rock out to Radiohead’s Paranoid Android, you know the band was referencing Marvin, the chronically depressed robot with a brain the size of a planet — voiced by Alan Rickman in the 2005 film adaptation.

8. This killer restaurant at the end of the universe.

9. Time is an illusion — and lunchtime doubly so.

10. The universe’s creation made a lot of people very angry and was widely considered a bad move.

11. Anyone who can be elected President shouldn’t be trusted to do the job.

12. If a Vogon ever, ever tries to read poetry to you, you should turn tail and run immediately.

13. Ford Prefect isn’t just the name of a British car.

14. You’re not the only one who could never really get the hang of Thursdays.

15. You can understand that an alien sent to study life on Earth would think cars were the dominant life-form.

16. But not why people spend so much of their lives wearing digital watches.

17. When in a bar in outer space, the best thing to order is a Pan Galactic Gargle Blaster.

18. If somebody suddenly thinks they’re a hedgehog, the best thing you can do is give them a mirror and some pictures of a hedgehog, and they’ll figure it all out soon enough.

19. Space is big. Really big. You just won’t believe how vastly, hugely, mindbogglingly big it is, to be honest.

20. Mice aren’t actually mice at all. Instead, they’re insanely hypersmart beings from another plane of existence. Also, they’re smarter than dolphins. Who are still smarter than humans.

21. That one can find tea on a spaceship. But it’s not really tea, it’s rather something almost but not entirely unlike tea. (Also, if you count the movies, there’s a tiny lightsaber that toasts bread while you slice it. Handy!)

22. You can spend a year dead to dodge your taxes. Good tip.

23. Sometimes your friends turn into penguins. Or sofas. It’s all a little weird.

24. Every once in a while, it’s absolutely terrific when somebody’s trying to kill you — it means you’re on to something.

25. The only thing that can break the speed of light is bad news.

26. Life is like a grapefruit, and some folks have half one for breakfast.

27. Ships can hang in the sky, but bricks can’t.

28. That you should always, always, always stay abreast of plans posted at your local planning department in Alpha Centauri.

29. That if you ever discover why the universe is here, it could be replaced by something even more bizarre and inexplicable.

30. And that might’ve already happened.

31. It’s possible to be your own great-great grandfather, if something goes wrong with a contraceptive and a time machine.

32. One of the greatest sources of power in the universe is Restaurant Math. Oh waiter, check please!

33. Anything that happens, happens.

34. You don’t want to go to Heaven with a headache.

35. 42.

Get The Brief. Sign up to receive the top stories you need to know right now. Please enter a valid email address. Sign Up Now Check the box if you do not wish to receive promotional offers via email from TIME. You can unsubscribe at any time. By signing up you are agreeing to our Terms of Use and Privacy Policy . This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply. Thank you! For your security, we've sent a confirmation email to the address you entered. Click the link to confirm your subscription and begin receiving our newsletters. If you don't get the confirmation within 10 minutes, please check your spam folder.

Write to Alex Fitzpatrick at alex.fitzpatrick@time.com.