Help decoding Running H/F variables with attibutes

[Rick Quatro]

Hello All,

I am trying to figure out how attribute-based Running H/F variables work. 
Here is are examples of a couple in a document I have:

<$attribute[Booktitle:book]>
<$attribute[Revision:book]>

I assume that the first is looking for the value of the Booktitle attribute 
on the book element, and the second is looking for the value of the Revision 
element on the book element. Is this correct?

Also, I notice something about attribute-based Running H/F building blocks 
that differs from paragraph- and marker-based building blocks: the document 
I am look at doesn't have a book element, but it still displays the value. 
In fact, I don't even have the book file where I assume the book element 
originates. Does this sound right? Thanks.

Rick Quatro
Carmen Publishing
585-659-8267
www.frameexpert.com