His comic book career after Superman was relatively unsuccessful , and by the mid-1970s Shuster had left the field completely due to partial blindness .
Shuster was involved in a number of legal battles over ownership of the Superman character .
Shuster 's comic book career Superman Superman was relatively unsuccessful , and by the Shuster Shuster had left the field completely due to partial blindness .
Shuster was involved in a number of legal battles over ownership of the Superman character .