Как работает цикл foreach с многомерными массивами?

"author_id1" => array 
	(
		"fullname" => "Александр Сергеевич Пушкин",
		"email" => "aspushkin@mail.com",
		"year_of_birth" => "1856",
		"books" => array 
		(
			"id_1" => array (
				"name" => "Анджело",
				"year" => "1833",
				"genre" => "Стихи",
			)
			"id_2" => array (
				"name" => "Зимний Вечер",
				"year" => "1825",
				"genre" => "Стихи"	
			)
		)
	)
);

foreach ($db_leabs as $value) {
	echo $value['fullname']." - " .$value['email']." - ".$value['year_of_birth']."<br>";
	
		foreach ($value['books'] as $massiv) {
			while ()
			echo $massiv2['name']." - " .$massiv2['year']." - ".$massiv2['genre']."<br>";
			}
	}
};