In this book, Katrina Hazzard-Donald explores African Americans' experience and practice of the herbal, healing folk belief tradition known as Hoodoo. Working against conventional scholarship, Hazzard-Donald argues that Hoodoo emerged first in three distinct regions she calls "regional Hoodoo clusters" and that after the turn of the 19th century, Hoodoo took on a national rather than regional profile. The first interdisciplinary examination to incorporate a full glossary of Hoodoo culture, Mojo Workin': The Old African American Hoodoo System lays out the movement of Hoodoo against a series of watershed changes in the American cultural landscape.

Throughout, Hazzard-Donald distinguishes between "Old tradition Black Belt Hoodoo" and commercially marketed forms that have been controlled, modified, and often fabricated by outsiders; this study focuses on the hidden system operating almost exclusively among African Americans in the Black spiritual underground.

The book is published by University of Illinois Press.