He is best known for his numerous newspaper articles about historical monuments, mainly in the French-speaking part of Switzerland, including his own drawings of the buildings.

He is read with more caution in university circles, being known as a "vulgarizer" and reflecting essentially the state of knowledge at the period of his publications, chiefly the 1950s.

Being an active teacher as well, he wrote papers on heraldry, on the history of the alphabet and on the drawing habits of children.

Berger's activities with Occidental began in 1928, when he became the editor of the magazine Svissia[2] (known as Helvetia from 1929) which continued publication until 1933.

He authored more than 20 books about art and historic monuments in Switzerland and a large number of thematic notebooks in Interlingua, especially on the history of international auxiliary languages.