I can't remember the name of the book ( but I'm 
sure you can find it on Amazon ) but it was a 
large book all about the films of Rankin/Bass.  
Each of their films had a whole chapter of 
content about their production severl pages 
long.  I know that they covered information 
on "Last Unicorn" there as well as "Flight of 
Dragons" ( one of my faves! ) and "The Hobbit", 
etc. etc....