This book shows how to warrant claims about causation in a particular place at a particular time, ‘here and now’, ‘there and then’ – ‘singular’ causation. Good warrant matters if your efforts to affect change are to work. But you cannot properly warrant that a relation obtains without understanding what that relation is. To this end, Part 1 offers a set of features that characterise singular causal relations. These make up a ‘thick’ theory of singular causation, offering far more information than the usual ‘thin’ definitions, like those based on counterfactual or probabilistic dependence, difference-making or production. Details about how causal processes work play a central role here. This theory then provides the grounds for, in Part 2, identifying and systemising what kinds of evidence can warrant singular causal claims. Part 3 shows how this account may be used in practice, using examples from child protection.