Final answer:
The story of the Ethiopian Eunuch's conversion is found in the book of Acts in the New Testament, depicting a significant moment in the early spread of Christianity.
Step-by-step explanation:
The story of the Ethiopian Eunuch's conversion to Christianity is found in the book of Acts in the New Testament. This particular event is a significant moment in the early spread of Christianity and is especially notable for its depiction of the early Christian community's outreach beyond Jewish communities. Acts is known for documenting the early church's expansion and establishment of Christian beliefs and communities, guided by the apostles and other key figures in the post-Resurrection era.