Conditional Tags for "Parent" Pages

Hi,

So I know this is basic, but i am not able to pull this off.
I have a parent page (not post) called “Books” and under that parent, I have more pages. So this is getting so old… to repeat over and over.

I am using something like this PHP for all features of the pages under “BOOKS” to uniquely use same banner, footer and other stuff.

elseif (is_page(‘books’)) { echo ‘background-image: url(‘.get_stylesheet_directory_uri().’/images/footer_band_brown.png);’; }

elseif (is_page(‘articles’)) { echo ‘background-image: url(‘.get_stylesheet_directory_uri().’/images/footer_band_brown.png);’; }

elseif (is_page(‘other’)) { echo ‘background-image: url(‘.get_stylesheet_directory_uri().’/images/footer_band_brown.png);’; }

Somehow – I can’t figure out how to make this IS_PARENT or IS_CHILD so I only have to make this code ONCE for all pages that have the parent “books”.

Any suggestions?
Thank you for your help.

Meekr