Other than the Tarkovsky's production, it's been adapted into movies rather badly, but Lem's Solaris is a fine read as well.

I feel like stepping outside native English works is a bit like cheating. 😃 There's a lot of super interesting European scifi. During the USSR it was a major form of escapism and veiled criticism all over Eastern Europe so that area alone yielded a massive amount of scifi, but there's a rich history of the genre all over Europe. Mostly it got translated to neighboring European languages, seldom to English, and even if it did most likely never reached other continents.

To fit the theme I will give some French examples because French scifi has some major wierdos:

• Pierre Stolze, "Marilyn Monroe et les samouraïs du père Noël" (Marilyn Monroe and Santa's samurais)
• Gerard Klein, "Les Seigneurs de la guerre" (The Lords of War)
• Pierre Barbet, "L'Empire du Baphomet" (Baphomet's Empire)

If you manage to read any of them I don't think you'll be dissapointed.