If you could recommend a single book to someone who does not like reading, what would it be and why?

Marli gave a very good answer.

I'm an avid reader but I have preferences. There are books and topics for which I have zero interest. If I am given such a book, even though I love reading!, I wouldn't want to read it. And the same is true about the stuff that I love to read; there are passionate readers who won't be interested in this stuff in turn.

Now, imagine if that is the case for folks who do love to read, how much more will it apply to someone who does not like reading.

Essentially, the key to your question would be to try to understand why this person doesn't like reading.

If they just haven't found the books that would spark their interest then the task is to find them (not that this is necessarily easy).

But there are people who simply don't like reading. My own brother is such a person even though the rest of the family and his wife love reading. He has other hobbies and that's just like that. If the person you have in mind falls into that category it might be difficult to change that.

Maybe one approach would be to interest them into comics and graphic novels to get them interested in reading stories. That might be a gateway drug if you will. But maybe not.

And of course, there's a great variety of comics/graphic novels, too.

I think you should know in which topics this person is interested: love, detective, horror, history ... Think about which movies this person loves to see.

I started reading a lot when I discovered the books of Stephen King because it's a mix of suspense and relationships between people. you can start which his short novel Shawshank Redemption (rated best movie ever on IMDB).

Or google for Maus made by Art Spiegelman. This is a graphic novel about the Second World War and between a comic book and a novel.

It would be a book about a subject the person is interested in. If reading is such a chore, the person won't read a book because he has to. He will read it because he wants to.