Gosseyn carries the burden of The World of Null-A's themes. His name is meant to be pronounced "GoSANE," and he exemplifies the advantages of Null-A thinking. Most of the other characters are essentially stereotypes whose behavior is predictable, although van Vogt succeeds in giving an air of mystery to Patricia Hardie, daughter of Earth's president, and Eldred Crang, leader of a secret base of the Greatest Empire and secret follower of Null-A.

Gosseyn has much in common with Jommy Cross of Slan (1946; rev. 1951).

They both are supermen. Gosseyn has extra brain matter that gives him extraordinary powers. Cross and Gosseyn both represent the next evolutionary step after modern man. Like Cross, Gosseyn is an especially attractive character for adolescent readers because he is a lonely figure who is persecuted by evil forces. His lashing out to destroy his enemies is very satisfying as a fulfillment of his vengeance...