Algis Budrys described "World of Ptavvs" as "snappy, ingenious, and upbeat", praising Niven for "treat telepathy as the phenomenon it should logically be". Alan Brink noted that "Niven has made a very effective use of a . A person who had not read the book has no way of knowing who or what 'Ptavvs' are; then you read it and find that we are ourselves Ptavvs and that Earth is the World of Ptavvs—as seen through alien eyes. The success of this book testifies to the effectiveness of Niven's curiosity-arousing device".