Homeopathy is a system of alternative medicine developed by Samuel Hahnemann over 200 years ago based on the principle that "like cures like." It involves treating the patient with highly diluted substances believed to cause symptoms similar to those experienced by the patient. Hahnemann made major contributions through several writings including Organon of Medicine, Materia Medica Pura, and Chronic Diseases. Homeopathy treats the whole patient based on their complete symptom picture rather than just their diagnosis.