Both the practical and logistical aspects of producing a piece of theatre and the historical and social evolution of theater are given thorough treatment in this introduction to, and explanation of, the tradition of the Mexican "pastorela." The descendant of a theatrical tradition that dates back to rituals of sacrament and religious offering in medieval Spain, the traditional "pastorela" focuses on the conflict between good and evil as experienced by the shepherds on their journey to witness the birth of Jesus.