Hermas was a Christian writer active in Rome during the first half of the 2nd century CE. He is known as the author of a single, influential work titled The Shepherd. According to early sources, he was the brother of a Bishop of Rome, and his own text presents him as a former slave who later worked in business.

His work, The Shepherd, is a series of revelations structured as Visions, Commandments, and Parables, delivered by an angelic guide. It addresses practical concerns within the early Roman Christian community, such as ethical living, the dangers of wealth, and the possibility of repentance after baptism. The date of its composition is debated; while some early tradition places it around the mid-2nd century, many modern scholars, based on the text's internal evidence, suggest it was written earlier, possibly in the first few decades of the century.

The Shepherd of Hermas was widely read and highly respected in the first centuries of Christianity, with some early theologians treating it with near-scriptural authority. It provides crucial insight into the moral and disciplinary questions facing early Christian communities. Although it was not included in the final New Testament canon, its preservation in major ancient manuscripts underscores its historical importance as a key document of early Christian life and thought.