Since Herbert Wechsler's famous article, the topic of neutrality has played central stage in many debates about judicial review specifically and constitutional law generally. On closer inspection, however, it turns out that the heading of "neutrality" encompasses not one but four different debates. One is about principled adjudication, another is about decision according to rules, a third is about substantive neutrality, and the fourth is about the desirability (or not) of designing the institutions of judicial review without regard to likely substantive outcomes and without regard to the likely staffing of those institutions. This paper distinguishes these four conceptions of neutrality and analyzes each of them.