Barthold Fles was born in Amsterdam on February 7, 1902. His family was Jewish but did not keep Jewish laws. His father, Louis Fles, thought that it was wrong for Jews and other people to be religious. Louis Fles imported typewriters and sold them, in addition to other office products, in several stores that he owned and to other stores. Barthold was his oldest son so his father wanted him to help him at work. Barthold did not want to work for his father. He only wanted to read. Barthold read in Dutch, German, English, and French. He read a lot and very fast. Barthold found a job at De Lange publishers. In 1923 he left for the United States.