I feel like this book was more in line with the Pirx the Pilot stories & remixed Asimov's robot puzzle stories too much to be his best. Cyberiad is the most fun, The Chain of Chance & The Investigation are better mysteries, Fiasco is a better veilled critique of Soviet groupthink (collective decision making) & alien encounters.

A Perfect Vacuum is my pick for his best, as it's heavily inspired by Jorge Luis Borges' works.