The terms ‘Salafist’ and ‘Jihadist’ appear on television and in our Facebook and Twitter feeds almost daily. But they have become akin to Orwell’s description of the word ‘fascist’, terms rendered ‘almost entirely meaningless’, so overused that they now convey little except in so far as they signify ‘something not desirable’. This is where Shiraz Maher steps in with Salafi-Jihadism, an illuminating and necessary book for our times. That the West is facing a jihadist challenge is indubitable. The questions are what, precisely, is the nature of that challenge, what is its ideological basis and where does it come from.