"The Book of the New Sun" by Gene Wolfe.

Its a cold open without exposition into an unknown world. Is it fantasy? Is it sci-fi? There's possible hints of both. The protagonist is the narrator and the character tells the story. Since the character already knows this world, he doesn't both explaining what is happening very often. The style of speech the character uses including the vocabulary isn't quite common. The storytelling is unforgiving because the protagonist has no frame of reference from our world to explain. There's even more to the difficulty in following the story than this, but some of that speaks to the plot points, so I won't explain further.

If you want a hard, but eventually rewarding read, go into it cold without reading any synopsis or reviews.

Here's the opening paragraph from the first page:

"It is possible I already had some presentiment of my future. The locked and rusted gate that stood before us, with wisps of river fog threading its spikes like the mountain paths, remains in my mind now as the symbol of my exile. That is why I have begun this account of it with the aftermath of our swim, in which I, the torturer’s apprentice Severian, had so nearly drowned."

Gödel, Escher, Bach: An Eternal Golden Braid by Douglas Hofstadter.

It's been a good many years since I had my nose in my copy, but I am glad I was able to read it at a time of my life that I could attain some appreciation and understanding of it. Right now, I don't think I could focus my attention long enough to get back into it.

I haven't sought out Hofstadter's other works, but if I could get that mindset back, I'd definitely consider it. I Am a Strange Loop is on my want-to-read list.

And if the surname seems familiar, a character in a popular TV show was given his surname on purpose by the writers.

Alan Lightman's book Einstein's Dreams. It uses stories to explore how time moves, or could move if the laws of the Universe were different.

Runny Babbit by Shel Silverstein

The whole thing is written in spoonerisms, and it can tret gicky to lead out roud ko a tid. Honestly, not his best, but certainly the most unique.

Riddley Walker by Russell Hoban. Set in a post apocalyptic England where all of society has broken down, even language. Stick with it, your brain will adjust and you won’t notice after the first chapter or so.

These are almost cheating, but I’ll go with Gravity’s Rainbow followed by Blood Meridian.

https://en.wikipedia.org/wiki/Gravity%27s_Rainbow

https://en.wikipedia.org/wiki/Blood_Meridian

I answer with this a lot on Lemmy but House of Leaves. That fucking book. Everyone should read it once. If you read it multiple times you are a crazy person, and if you are not: trying to understand it will MAKE you a crazy person.

Let me look through my growing library-called-a-room:

It might be considered a "safe," or "of course it is," pick, but "Love Me For Who I Am," would be my answer. It is a series that helped me understand myself a lot, and I credit it for helping me understand the complicated feelings I had inside when searching for who I really was and how to engage with the world around me. On the heels of that, "Is Love The Answer?" is a one-shot that is a phenomenal read exploring the spectrum of Aromanticism. Imagine that recommendation coming from me cough bio cough, but seriously, those two reads I think can safely be called cornerstones of my reading journey. I have read many amazing series(SAO:Progressive the LN(not the fake other ones), Drugstore In Another World, When Will Ayumu Make His Move? and otherwise), but those two really helped lay out in print what I could not put into words, and showed that there was an answer.

All of the ones I mentioned I would recommend, but those first two would be my genuine answers to your question.

the Amber books by Zelazny

Get yourself a bit of Christopher Moore or some Neal Stephenson.

Tim Dorsey was great up until the end although there was a lot of same-ness about much of his work.

Work your way through Cory Doctrow's catalog of unique fiction.

I love almost everything by Dean Koontz - he is a magical phrase turner.

You can always sell me on a Kaiju novel.

"House of Leaves" made me throw it against the wall.

I did like "XX" a novel by Rian Hughes. Different characters 'speak' in different typefaces, and the story zips through time and space.

"The Iron Dream" by Norman Spinrad is a massive mindfuck. The forward explains that Adolph Hitler came to America in 1922 and managed to find work illustrating science fiction pulps. Eventually he felt confident enough to start writing in English. This book is his masterpiece.

"Flashman" by George Macdonald Fraser. The author follows the career of a successful Victorian gentleman, General Sir Harry Flashman, VC. Flashy is a slaver, rapist, murderer, liar, cheat, coward, and scoundrel who has decided to write his memoirs for posterity.

Not me, but my spouse read House of Leaves

How many times are you AI bots going to ask this question?