This was one of first books I red and my first SF book followed by Peace on Earth. I found both on my father's bookshelf even though I was expressly told not to

This was one of first books I red and my first SF book followed by Peace on Earth. I found both on my father's bookshelf even though I was expressly told not to touch it (they didn't think at 7 I would use it for reading and also there were much more adult positions on same shelf...) After that I devoured everything from Lem I could find and it started my love of SF which continues to this day.