Martin P. Nilsson (1874-1967) was a Swedish classical scholar and professor of ancient Greek religion and archaeology. He made significant contributions to the study of ancient Greek religion and mythology. In "Greek Popular Religion," Nilsson focuses on the religious practices of the everyday people in ancient Greece, including their beliefs in deities, cults, festivals, and rituals. The book explores how religious practices were integrated into daily life and how they differed from the formalized state religion and the beliefs of the educated elite. Nilsson draws on a variety of sources, including literary texts, inscriptions, archaeological evidence, and comparative studies, to provide insights into the religious beliefs and practices of the common people. He examines topics such as household worship, rural cults, magic and divination, and the role of women in religious rituals. "Greek Popular Religion" is considered a seminal work in the field of Greek religion and provides a comprehensive and accessible study of the religious life of the common people in ancient Greece. While some of Nilsson's ideas and interpretations have been subject to revision over time, his book remains a valuable resource for understanding the religious beliefs and practices of the ancient Greeks beyond the realm of the formalized state religion.