Baedeker to have three of his four sons − Hans, Ernst and Dietrich − beside him in the firm, as editors and writers. Karl Baedeker III, the fourth son, entered academia and rose to become a professor of physics at the University of Jena. He was killed in action at the Battle of Liège in August 1914. It was his son Karl Friedrich who revived Verlag Karl Baedeker after the Second World War. During his reign, which lasted over 50 years, Fritz produced 73 new "Baedekers", as they came to be known universally. The Baedeker travel guides became so popular that
Karl Baedeker (scientist) This was the first example of doping a semiconductor to change its properties and also the discovery of transparent conductive materials. He also observed a Hall effect in transparent copper iodide thin films that had the reverse sign to that in copper, an observation of what was later to be known as conduction by electron holes in semiconductors. This observation was critical in developing the theory of electron conduction in solids. Along with his graduate student Karl Steinberg, Baedeker studied the effect of varying concentration of iodine on the electrical properties of copper iodide. He also is credited with making