Abstract
After the attempts at unifying the electromagnetic and gravitational fields by H. Weyl and A. S. Eddington, A. Einstein quickly became a central and driving figure in this research. His concept of unifying fields via geometry was taken up by others like E. Schrödinger in Dublin, M.-A. Tonnelat in Paris, B. Finzi in Milano, V. Hlavatý, Bloomington, Indiana, and their collaborators. Larger groups also existed in Japan and India. Worldwide, not many more than 170 physicists and mathematicians took part in this research. After a sketch of the geometrical and physical concepts involved, I briefly describe some scientific relations among various persons/groups and the changing interest in research concerning classsical unified field theory during the period investigated.