Lem was a Polish SF writer, occupying a strange place within the genre. He despised most SF (Dick was the only American SF writer he admired – an opinion that was not remotely reciprocated) for its vacuity and shallowness, which accurately implies the seriousness and philosophical bent of his own work.

His most famous novel is Solaris, made into a great film (the Tarkovsky version is my favourite science fiction movie) and later a decent one. It concerns a first contact with aliens: the distinct idea behind most of Lem’s several approaches to this standard SF trope is that Lem believed communication with an alien mind, or comprehension of it, would be all but impossible. (I imagine Tarkovsky felt the same, as he also adapted the Strugatsky Brothers’ Roadside Picnic as Stalker, and that expressed a similar position.)

Lem was also, extraordinarily in this genre, something of a luddite: he regarded many scientific advances, real ones and those portrayed in his fiction, as a bad thing, as a move away from and enemy of the better human traits. He wrote little SF later in his life, instead pronouncing on technology and the future – he was very against the internet, for example.

This all makes him sound grim and po-faced, and some of these works are indeed among the most demanding SF ever written. However, he also wrote some extremely funny stories, generally about a robot civilization. The Cyberiad is hugely imaginative and varied, and often hilarious. There’s a brilliant story about a poetry machine that must have been one of the hardest things ever to translate, this side of Georges Perec.

There is other work worth reading too: collections of reviews of or introductions to nonexistent books, for instance. His essays on SF and science are very astute too – he was writing about the human implications of things like virtual reality and nanotechnology over 50 years ago.

He’s well worth trying, but you might want to choose carefully, as I suspect different works will appeal to different readers.