"The ingathering of the exiles to their ancestral homeland is the raison d'etre of the State of Israel. Aliya (literally ascending) is the Hebrew word for immigration to the Land of Israel. The meaning of ascent in this context is spiritual as well as physical; all Jews are educated in the belief that this ascent is an essential part of Judaism. It is the ultimate form of identification with one's people, the Jewish people, whose life and destiny are inextricably tied to the Land of Israel. Since the beginning of the waves of aliya in the late 19th century, many hundreds of thousands of immigrants have arrived in the Land. The background, traditions and expertise brought by each wave have been of immeasurable value in the development of Israel's pluralistic, democratic society and modern economy."

Aliya and Absorption, Israel Ministry of Foreign Affairs


Here you can find a lot of information on Aliya, including "The Law of Return", and absorption process.