The Invention of the Jewish People...

is a study of Jewish historiography by Shlomo Sand, Professor of History at Tel Aviv University. It has generated a heated controversy...
the appearance of millions of Jews around the Mediterranean and elsewhere as something that came about primarily through the religious conversion of local people...

Sand argues that it is likely that the ancestry of most contemporary Jews stems mainly from outside the Land of Israel

https://en.wikipedia.org/wiki/The_Invention_of_the_Jewish_People