$post_author: WP_User Object
(
    [data] => stdClass Object
        (
            [ID] => 143
            [user_login] => william-norman-grigg
            [user_pass] => d04afabdd6d0b15fc84c39ea480e8358
            [user_nicename] => william-norman-grigg
            [user_email] => [email protected]
            [user_url] => 
            [user_registered] => 2011-12-07 15:12:12
            [user_activation_key] => 
            [user_status] => 0
            [display_name] => William Norman Grigg
            [type] => wpuser
        )

    [ID] => 143
    [caps] => Array
        (
            [author] => 1
        )

    [cap_key] => wp_capabilities
    [roles] => Array
        (
            [0] => author
        )

    [allcaps] => Array
        (
            [upload_files] => 1
            [edit_posts] => 1
            [edit_published_posts] => 1
            [publish_posts] => 1
            [read] => 1
            [level_2] => 1
            [level_1] => 1
            [level_0] => 1
            [delete_posts] => 1
            [delete_published_posts] => 1
            [email_single_user] => 1
            [email_multiple_users] => 1
            [tablepress_edit_tables] => 1
            [tablepress_delete_tables] => 1
            [tablepress_list_tables] => 1
            [tablepress_add_tables] => 1
            [tablepress_copy_tables] => 1
            [tablepress_import_tables] => 1
            [tablepress_export_tables] => 1
            [tablepress_access_options_screen] => 1
            [tablepress_access_about_screen] => 1
            [author] => 1
        )

    [filter] => 
    [site_id:WP_User:private] => 1
)

get_the_author_meta: 

$bio: William Norman Grigg publishes the Pro Libertate blog and hosts the Pro Libertate radio program

$bios: Array
(
    [0] => William Norman Grigg publishes the Pro Libertate blog and hosts the Pro Libertate radio program
)

William Norman Grigg publishes the Pro Libertate blog and hosts the Pro Libertate radio program