Oh sure, so you like those 'serious' Lem's books. That' great, we've got plenty. I think you could try:
- "Summa Technologiae", it's not exactly a novel but a discourse, still you should find it interesting. I think.
- "Fiasco" is a novel, also dealing with problem of 'contact' between Humanity and another race (when I say 'also' I mean it resembles "HMV" a little by this).
- "Solaris" definitely on of the best works about aforementioned 'contact' ever written, however the contents of this brilliant piece cannot be summed up to just that, there's much more.
Now it's up to you. Please come back with post-reading reflections:)