The story
The original Swiss publishers program focused on regional literature. In the 1920s the sons of Emil Birkhäuser established a basis for the current scientific program with academic journals and reference books, later progressing to textbooks and monographs in the natural sciences. (The company was formally known as "Verlag Emil Birkhäuser & Cie. A.G." back then.) In the 1940s the scientific segments were expanded and gained international recognition. Publications in civil engineering followed as did further journals and book series in the ensuing years. In the 1960s the publishing program was expanded to incorporate architecture and art of famous painters, lithographs and gravures. Birkhäuser opened a branch office in Boston, Massachusetts, USA in 1979 which focused on mathematics and theoretical physics. From 1985 to 2010 Birkhäuser entirely was a part of the Springer Group.
From Wikipedia’s article on Birkhäuser, shared under CC BY-SA 4.0.4