Display additional column in post/custom post list in Wordpress

wp_custom_edit_post_column.php

/*
   Version Tested: 3.6, 3.8
*/

/* Display custom column */
function display_posts_stickiness( $column, $post_id ) {
    the_author();
}
add_action( 'manage_posts_custom_column' , 'display_posts_stickiness', 10, 2 );

/* Add custom column to post list */
function add_sticky_column( $columns ) {
    return array_merge( $columns, 
        array( 'author' => __( 'Author', 'wotheme' ) ) );
}
add_filter( 'manage_posts_columns' , 'add_sticky_column' );