In Daniel Silva's seventh Gabriel Allon thriller, The Secret Servant, the Israeli spymaster takes on Islamic extremists based in Europe.

You're obviously deeply concerned about the threat of Islamic terrorism.

I've been peeling away at it in layers. The last book, The Messenger, dealt with Saudi Arabia and its financial links to the global jihadist movement. The Secret Servant has two general themes: the threat from the radicalized young Muslims in Europe and those in Egypt. In many ways the European Islamists are more violent, more toxic than they are in Cairo. There are radical mosques and terrorist recruiters all across Europe. The European security services are doing the best they can, but I wouldn't be surprised if the next time we're hit by al-Qaeda, the people who do it are carrying European passports.

You mean the next time we're hit in America?

Yes, America. The European communities made terrible mistakes bringing so many immigrants in as guest workers; they treat them as second-class citizens, they are marginalized, and they are ghettoized. In many of the Islamic communities in Europe their customs and their ties are to their home countries rather than to the country where they have chosen to live. Lots of people born in Holland don't speak Dutch very well so there's this barrier; they're trapped between two worlds and they find shelter in Islam and radical Islam. It's a threat to the European countries, but it's a threat to us as well.

How?

The Europeans have terrible demographic issues. Their own population numbers are slipping and still they need workers to support their social welfare programs. So it's going to be interesting to watch for a very long time. I think that our security depends on them getting it right. Europe cannot remain a breeding ground for terrorists. I'm very pessimistic about the future in Europe in terms of how they're going to accommodate and assimilate large numbers of Islamic immigrants. I hope I'm wrong.

What's next for Gabriel Allon?

I'm fascinated by what's going on in Russia today: the return to centralized authoritarian rule, the crushing of antigovernment demonstrations, the killing of journalists who have dared to poke their nose into things the powerful don't want them to know. I never had a chance to write a Cold War novel-it ended before I became a novelist-but I think it might be time to write about the new Russia, and the new Cold War that might be looming.