Paget's disease is a non-inflammatory bone condition characterized by increased and irregular bone remodeling leading to weakened and deformed bones. It affects approximately 3% of the European population over age 40. The pathogenesis may involve a slow virus infection. Clinical features range from being asymptomatic to bone pain, fractures, deformities, neurological symptoms, and high output heart failure. Diagnosis involves clinical assessment, blood tests, imaging studies showing three distinct phases of bone involvement. Treatment focuses on pain relief, drug therapy to slow bone turnover, and surgery for complications like fractures or joint deformities.