Pfizer Inc. is a prominent American multinational pharmaceutical and biotechnology corporation, headquartered in Manhattan, New York City. Established in 1849 by Charles Pfizer and his cousin Charles F. Erhart, the company initially focused on fine chemicals before transitioning to pharmaceuticals, especially after the discovery of oxytetracycline in the 1950s. Over the years, Pfizer has developed a wide range of medicines and vaccines across various therapeutic areas including immunology, oncology, cardiology, endocrinology, and neurology.