Unhealthy churches are the cause of many problems. These churches mislead those who do not understand Scripture well. They also dishonour the name and holiness of the Lord. The introduction to this book outlines the marks of a healthy church. Historically, the marks of the true church have included the true preaching of the Word, the proper observance of the sacraments, and the faithful exercise of church discipline. The author reflects on these aspects, as well as additional characteristics of a church working for the glory of God.