In these testing times, more than ever we all tend to look to our own. So Harris's warning in this extended essay - that we ignore at our peril the rise of fundamentalist Islam - may well go unheeded. That would be a shame. It would also, as the sovereign wealth funds of (mostly Muslim) petro-states buy up “distressed” Western assets, be an irony.

Harris's thesis is that, in their support of individualism, liberal democracies inevitably misunderstand and/or mistake systems that differ - most obviously the Islamic theocracies. What we often parody as fanatical is, he argues, simply different. He traces the long march of Islam and finds the constant themes in its pluralities. Many of those are familiar with the Western way, but opposed to it. Harris points out that some of the 9/11 terrorists visited strip clubs and used the internet for pornography, yet died and murdered for what they believed in. He cautions that “the birthrate of the native Europeans continues to fall, while the birthrate among the Muslim immigrants is explosive”.

Harris's central antithesis - our “exaggerated confidence in the power of reason” against the “forces of fanaticism” - may be over-simplistic and pay insufficient attention to the schismatic nature of the Islamic world. Nor does he say enough about possible solutions. But this still is an important, thought-provoking and salutary book. We should all hope that Harris is not reduced by stuttering economies to the status of a Cassandra.

The Suicide of Reason: Radical Islam's Threat to the West by Lee Harris
Basic Books, £9.99 Buy the book

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