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 on the title pages in both languages, further increased its sales, as his brother Adolph, who had opened a bookshop of his own in Rotterdam that year, sold it in Holland and also managed its sales in England. However, very few copies of the first edition have survived, which has made it one of the rarest and most sought-after Baedeker publications of all time. The "Conversationsbuch für Reisende" ("The Traveller's Manual of Conversation"), in four languages (English, German, French and Italian) which appeared later was based on this manual and for a long time, the stereotype editions remained unrivalled in