While the process by which a person becomes part of a terrorist group is different in every case, there are patterns and similarities in the ways people are radicalised. Identifying them is a big part of what our security services do nowadays, looking at individual behaviour to try to understand who may end up taking a path towards violence. Joan Smith’s new book, Home Grown, seeks to identify one set of indicators, focusing on misogyny and domestic violence. It is not based on data-driven research. Rather, it relies on anecdotal evidence, drawing on a somewhat random set of case studies from Western societies in recent years. But that does not stop it from being a very stimulating meditation on a topic on which gallons of ink have already been spilled.