Despite the major advances that have been made since the founding of the NARPD 25 years ago, particularly in terms of treatment of the disorder, one major question has yet to be answered: What causes Paget’s disease? This question has perplexed many investigators since Sir James Paget first accurately described the disorder over 120 years ago. Paget thought that the disorder was inflammatory in origin, hence his term osteitis deformans. However, over the past 20 years, workers have concentrated on a potential viral etiology. To ascertain whether paramyxoviruses are involved in Paget’s disease, I feel it is necessary to answer four major questions:

1. Are paramyxoviruses present in pagetic bone? 2. Is there evidence to suggest how they got there, and any predilection of the viruses for bone? 3. How do the viruses cause the disease? 4. What else do we know about the disease that can be explained by a viral etiology?