There are about 2.2 billion Christians in the world and even if you’re not one of them, odds are you know about the religion and you even might celebrate some of the secularized versions of Christian holidays. If you’re looking to understand more about this faith, its history, and its many denominations, here are some books to help you get started.

Christianity: A Very Short Introduction

Journeys to Heaven and Hell: Tours of the Afterlife in the Early Christian Tradition

After Jesus, Before Christianity: A Historical Exploration of the First Two Centuries of Jesus’ Movements

The Making of the Bible: From the First Fragments to Sacred Scripture

The Genius of Jesus: The Man Who Changed Everything