Directives within .htaccess files apply to the directory that contains the .htaccess file and all its descendants.

Directives within the file,
/home/users/jh1636/public_html/.htaccess
would apply to all files within and "under" the public_html directory for the user jh1635.

Directives within the file,
/home/users/jh1636/public_html/books/.htaccess
would apply to all files within and "under" the public_html/books directory for the user jh1635.