From eighteenth-century slave rebellions to contemporary responses to police brutality, Caribbean methods of problem-solving “spiritual work” have been criminalized under the label “obeah.” Connected to justice-making force, obeah remains a crime in many nations of the anglophone Caribbean today. Experiments with Power addresses the complex question of what obeah is, providing the first book-length ethnography devoted to the subject. Instead of arguing for obeah’s decriminalization under terms of religious recognition enshrined in most modern constitutions, this work shows how obeah lays bare the moral and racial foundations of modern ideas of religious tolerance. Tracing these ideas back to the Enlightenment, this book examines how such tolerance was premised upon the idealized separation of religion and power. Although this separation has undergirded ideas of secularism for centuries, religion remains entangled with questions of power and justice in contemporary worlds. This entanglement is common, but the ways that it has been mobilized to criminalize or denigrate certain practices as “black magic” reveals the interrelation of religious and racial discourses. This book details how the exclusion of obeah and other racialized tropes of “black magic” have defined religion from the eighteenth century to the present. Rather than seeing Afro-Caribbean spiritual workers as overdetermined by these influential discourses, this monograph shows how they elaborate alternate theories, describing their practices with terms that are often taken as antonyms for religion—science, work, or criminal justice. Experiments with Power argues that these theories redefine popular and scholarly understandings of religion, offering new ways to theorize religious practice.