Leprosy, also known as Hansen's disease, has a deep historical significance and is caused by the bacterium Mycobacterium leprae. This chronic infectious disease primarily affects the skin, peripheral nerves, and mucosal surfaces. The exact mode of transmission of M. leprae is not fully understood, but it is thought to occur through respiratory droplets. Historically, leprosy has been stigmatized, leading to social exclusion and isolation of affected individuals. The disease has two main forms: tuberculoid leprosy, which is milder and characterized by skin lesions with well-defined borders, and lepromatous leprosy, which is more severe and involves widespread skin lesions and nerve damage. The pathogenesis of leprosy involves a complex interaction between the bacterium and the host's immune response. M. leprae has a predilection for peripheral nerves, leading to sensory and motor impairments in affected individuals. The disease's spectrum varies, with some individuals having paucibacillary (few bacteria) and others having multibacillary (many bacteria) forms. Diagnosis is primarily based on clinical features, skin biopsy, and acid-fast bacilli staining. Multidrug therapy, involving a combination of antibiotics such as dapsone, rifampicin, and clofazimine, is the standard treatment for leprosy. Early detection and treatment are crucial to prevent complications and disabilities.