Books where character has to explore things inside their own minds/memories

[Tess]

I'm looking for books that have a similar theme where a character kind of runs through their own heads to explore ideas or try to remember things.

In book form, the only one I can really think of is Passage where the main character keeps running through different memories inside her head trying to find out what Near Death Experiences are all about.

Mostly I've seen this in movies - Inception, Eternal Sunshine of a Spotless Mind, or parts of Captain Marvel.

I'd love suggestions! Thank you!

[Helena]

Challenger Deep is amazing and half of the book takes place in the mind of the protagonist.

I'd also argue for Slaughterhouse-Five but that depends on how you read it.

[Tess]

Helena wrote: "Challenger Deep is amazing and half of the book takes place in the mind of the protagonist.

I'd also argue for Slaughterhouse-Five but that depends on how you read it."
Thanks!
Slaughterhouse Five is on my TBR list, but now Challenger Deep is, too. I like Neal Shusterman a lot.

[Helena]

Np! :)

There's also this book, which I haven't read yet, but it seems right up your alley: Solaris.

[Tess]

Excellent! thanks!

[Rainbowheart]

Memento Mori
Escape to Witch Mountain