Stanislaw Lem's most well known novel is Solaris (1961) because it has been the basis of several movies, not because a lot of people have read it.
There are of course the 'Solaris" movies one made in Russia in 1972 by Andre Tarkovsky and the recent American remake in 2002. Lem has been critical of both. While Tarkovsky can be faulted by Lem he himself has been subjected to the Soviet Censors as Lem has.
Tarkovky's earliest film Ivan Rublev has been yet to be released in its full form having suffered the worst excesses of American cut and paste editing as well as Soviet censorship. It is a tale not unlike that of the Wickerman.
But before these two versions of Solaris there were two B Grade movies that were based on Solaris or the theme of Solaris.
The first is Journey to the Seventh Planet. Which was originally made in 1962 not 1959 as mistakenly listed here;