Just like other experts, members of the professions develop their craft thanks to a deep internalisation of both complex cognitive structures and a mix of habits and intuitive understandings. These non-cognitive aspects of expertise can be what distinguishes the merely competent from the truly brilliant. Yet habits can also be what makes us blind to important features of the world we inhabit. In the life of a professional, these features include the vulnerability of those seeking her services, which in turn grounds the professional's particular ethical responsibility. This book develops an in-depth account of habit to understand its impact upon the way moral decisions are made in a professional context. Its central thesis is the following: what most often stands in the way of a professional meeting her ethical responsibility is not so much stupidity (or character defects) but rather the deleterious aspects of habituation. This book calls for renewed attention to be paid to habits and their relationship to ethical agency. Mostly neglected in moral and legal theory, such an inquiry not only conditions an adequate understanding of the risks inherent in a legal system's institutional structure. It is also essential if we are to come to grips with the challenges raised by the professions' growing reliance upon automated systems.