It's an "anti-mass-immigration" book by an Englishman, or rather, a Euro-person located on the island of Great Britain. It is uniformily calm and rational throughout.
To give you a flavor of the book, 2/3 of the way through the book he might have hit the essence of the problem:
The problem is one that is easier to feel than it is to prove, but it runs something like this: that life in modern liberal democracies is to some extent thin or shallow and that life in modern Western Europe in particular has lost its sense of purpose.That statement made quite an impact on me, in part because I was simultaneously reading a book by the famous Catholic historian, Hilaire Belloc, "The Great Heresies." In his chapter on Islam, he reminded the reader how recent the European dominance of Islam was.
He wondered if the pendulum would swing back the other way, that is, towards the domination of Europe by Islam. It was fascinating to watch him think out-loud (in 1920's) about how this Islamic resurgence might happen. He never guessed that Europe would someday willingly surrender to Islam, as it now is.
I eagerly look forward to seeing how Murray's book ends. For my part, I see Europe's problem as basically that of Icarus, in the Greek myth. They flew so high in the age of Enlightenment. And yet the program was essentially negative: they destroyed Christianity, which is what had given Europe its identity.
They never found anything to replace it with, other than the soul-less secular religions of Democracy (number-worship), Jacobin Equality (envy worship), Utilitarianism (comfort worship), Nationalism (state worship), and Socialism (bureaucracy worship). Daily life is protected against this existential angst by trivial busy-ness.
Quoting Murray again:
After all, how long can a society survive once it has unmoored itself from its founding source and drive?