Ernst Abbe was a German physicist and optician born on January 23, 1840. He is best known for his contributions to the field of microscopy and for developing the Abbe sine condition, which describes how light behaves in optical systems. Abbe worked closely with Carl Zeiss, a prominent lens manufacturer, to improve the quality of microscopes. In addition to his work in optics, Abbe was also a social reformer. He believed in the importance of education and established the Abbe School in Jena, Germany. His efforts helped advance both scientific research and social responsibility in the late 19th century.