body: Let's say, I want to make a computer video game that is based on some book.
  
  
  As far as I am concerned, to make such game a reality, I need to acquire the rights.
  
  
  How can I achieve that goal? Should I contact for such issue book publisher by email?
  Or there's some government entity which processes such inquiries?
  
  
  I'm interested in specific case, when author of the book died long ago.
  
  
  I understand that I probably didn't do enough research on that topic, but I really like to have any advice, at least where should I start my search.
  
  
  
title: How to find a rightholder?