function showBookContent (id)
{
    var pieces = new Array (
	'read_book_plot_summary',
	'read_book_characters',
	'read_book_interviews',
	'read_book_press_kit' );

    // loop through all pieces, enabling/disabled as needed
    for (var i = 0; i < pieces.length; i++ )
    {
	var obj;
	var value;

	if ( pieces[i] == id )
	    value = "block";
	else
	    value = "none";

	obj = myGetElementById (pieces[i]);
	if ( obj )
	    obj.style.display = value;
    }

    return false;
}