1939 was during the War period not before. Immigrating out of German started in the early 1930s. Nazis were in power in the 1920s, not fully. It was around 1928 they started the Culture Wars against ideas and works they deemed Modern, like Jazz. As the book states, the UK was pushing for them to immigrate there instead of their main Island because of antisemitic views. [1] [2]
The author actually traveled and talked to number of celebrities that lived during that time period. Even asking the Nazi era actors if they thought their careers would of took off if fascism never took hold and removed their competition.
[0] https://en.wikipedia.org/wiki/List_of_countries_that_have_ga...
[1] https://www.ourmigrationstory.org.uk/oms/jewish-refuge-and-t...
jewish immigration to mandatory palestine was always severely restricted by british. british were capturing illegal new immigrants and were shipping them off to cyprus or something like this. on the other side arab immigration through syria/trans-jordan/sinai was unrestricted
https://www.jewishvirtuallibrary.org/jewish-immigrantion-to-...
Near the end it goes into percentages of which counties Jews moved to and why during their immigration. A good portion of the UK was antisemitic, along with a number of other countries, and didn't want them moving to their country.
UK colonized part of Palestine at the time and pushed Jews to move there. Only the most devoted that wanted to be closer to their religious holy land went because the only work at the time was farming. Ones that wanted to maintain living off their crafts; acting, music, writing moved else where.
UK's antisemitic view actually help create Israel and push for the Zionist movement.
One of the most surprising aspects is that a number of Jewish immigrants actually supported fascism and told themself that it just was not implemented right. It wasn't until the 1960s when the views changed to fascism is bad.
Warning, the book is very dry and goes into detail of what happened to famous actors, writers, and musicians.
[0] https://yalebooks.yale.edu/book/9780300253375/culture-in-naz...