A catechism is a book of questions and answers that teaches the core beliefs of a religion, most commonly Christianity.

For centuries, churches used catechisms to help people, especially children, learn what their faith taught about God, right and wrong, and how to live. A typical catechism might ask, “What is prayer?” and then provide a clear, memorable answer that students would learn by heart. The questions build on each other, starting with basic ideas and gradually covering more complex theological concepts.

The most famous catechisms were written during the Protestant Reformation in the 1500s, when different Christian groups wanted to clearly explain what made their beliefs distinct. Martin Luther wrote a Small Catechism with simple explanations for families, and a Large Catechism with more detailed discussions for pastors and teachers. The Catholic Church produced its own catechisms, including a major one after the Council of Trent.

Learning a catechism meant memorizing these questions and answers, similar to how you might memorize multiplication tables. A child might recite their catechism in Sunday school, demonstrating that they understood their faith's teachings. While memorization has fallen out of fashion in many modern churches, catechisms remain important historical documents showing what different Christian groups believed and taught.