The Bavarian forest officer August von Krempelhuber (1813-1882) is one of the famous lichenologists of the 19th century. He is the author of the first and still unique lichen-flora of the state of Bavaria, author of the extremely detailed “History of lichenology and its literature” (3 volumes) and of many papers recording and describing lichens from various parts of the world. More than 400 species new to science were described by him. Based upon newly available historical documents collected by the Krempelhuber-family and particularly upon the examination of his many letters he sent to the lichenologists Ferdinand Arnold and Johannes Müller Argoviensis, a more detailed biography is presented here for his bicentenary birthday. His letters mirror his lichenological activities and the development of his scientific projects. They also mediate a vital picture of his character and spirit.