The lecture by Dr. Wolfgang Steinicke describes the epochal work of William and Caroline Herschel. It focuses on deep-sky objects, visually observed between 1774 and 1817 with various telescopes. Most of these were discovered in the monumental campaign (1783-1802), aided by his talented sister. 2500 nebulae and star clusters were published in three catalogs. William’s exploration of the skies from southern England also covered binary stars and objects in the solar system - with the height of the Uranus discovery in 1781. However, the man of German descent was far more than just an observer. He constructed large telescopes, developed new methods, and pondered the nature and evolution of cosmic objects, resulting in a revolutionary view of the structure of the Milky Way.