PyAmazon and Book Descriptions

[popjack]

First off, I'm new to Python, so please forgive if I've overlooked
something obvious. I work for a publisher and I'm trying to use
PyAmazon to programmatically examine our books' listings on Amazon.com.
One of the crucial fields for this task is Book Description, which is
not one of the available elements, or Bags. Is there a reason why this
is the case?

I've tried to add this field to the query using language found in
broader documentation for Amazon Web services, but no luck. Any insight
would be greatly appreciated. 

Thanks.