Since the Second World War, over 1000 Brethren churches have ceased to exist in the United Kingdom, the historic heartland of the Brethren movement. Decline is happening in other Western countries too. Yet God is also working powerfully in many places. God's Word teaches us that the causes of church decline are spiritual and so is the cure. Assembly Autopsy identifies four causes of spiritual sickness that need to be remedied, and outlines five principles of how God works by His Spirit to bring blessing and growth for His glory.