Threatened sets out the types of extremism the world has seen in recent times and the alarm that has been raised about what might happen in the future.Case studies from Australia and around the world illustrate the level of extremism that is prevalent-from antisemitism to terrorism with actions taken by authorities in Australia and around the world are highlighted.In this book, questions are answered about how citizens can identify extremism, radicalisation and subversive behaviour and what to do about it.