Starting at the very edge of current theories of artificial intelligence, communications, cosmology and nuclear strategy, Mr. Lem soars out into dizzy flights of speculation, grafting one field onto another to populate whole new realms of possibility.

(...)  As he moves further away from personal relations, and casts a more sardonic eye on the tricks that humanity's Faustian intelligence plays on itself, Mr. Lem has come to identify with such writers as Swift and Voltaire.

Paul Delany, The New York Times Review of Books

Fiasco will come to be regarded as one of the great SF novels...  It is a remarkable achievement, even for Lem;  for us, it is a most moving experience.

The Times