Everyone who has written a science fiction book apparently considers themselves an armchair philosopher. It all has to be a metaphor, all the time, apparently; not just any metaphor, no, a metaphor that the author has to explain in excruciating detail because he doesn't trust his audience to pick up on his subtleties!

Solaris - the planet - is a truly fascinating concept. An ocean-planet with two suns, a planet that seemingly controls the environment around it, seemingly able to create.

And I do love an ending where the central mystery of the book isn't answered - and it's not. We never find out if the ocean is living, is a brain, or is just a bizarre geologic structure.

Unfortunately, Lem ruins all of it through Kelvin, who painstakingly infodumps about the physical, biological, and philosophical theories about the planet that literally only exist in his made-up universe. If I wanted to read a textbook, I would've read a textbook.

At times, I found myself engaged with Kelvin's and Rheya's dynamic: their desire for each other;

Kelvin's guilt over Rheya's suicide; Rheya's belief that she truly is Rheya, which turns into the reader's belief; the horror Kelvin feels when seeing Rheya's reappearance, or when she stole the tape recorder;

and all of that turning into a burning need to be with each other despite all logic. But at the end,

when Rheya dies,

Kelvin gets over it basically immediately. Even from the start, it's obvious to the reader that Rheya is a blank character, as most female characters are when written by men. There's nothing interesting about her except as Kelvin's dead wife. She's obedient and docile, but hysterically suicidal whenever Kelvin shows any apathy towards her whatsoever. Women, amirite?! *rolls eyes*

I can see the appeal of Solaris, and it was appealing to me, at times. But the characters are hollow and unlikable with no clear motivations, it's interspersed with long tirades about philosophy and science and religion that have nothing to do with the plot at hand, and even the plot itself seems to be serving that singular purpose as a playground for Lem's own interest in such dense topics. Either he didn't have the decency or the skill to at least veil the metaphor in plot. In a word, it's boring. 

I really liked the premise of the book. The maybe sentient alien ocean and isolated scientist interacting, is just a really good setting to explore characters. And while I love detailed and thorough worldbuilding, the chapters about the research history read like a physics textbook and dropped way to many names for me to follow. The super detailed descriptions of the ocean's visuals also lost me a bit, it was just too much detail for me to imagine.
The more character and dialogue heavy chapters were fun, tho. My personal favourite was Rheya (or better, her copy). I actually think, this whole story from her POV would be a way more interesting horror read.