A debate on magnetic current: the troubled Einstein–Ehrenhaft correspondence

The unconventional correspondence between physicists Albert Einstein and Felix Ehrenhaft, especially at the height of the alleged production by the latter of magnetic monopoles, is examined in the following paper. Almost unknown by the general public, it is sometimes witty, yet it can be pathetic, and certainly bewildering. At one point the arguments they exchanged became a poetic duel between Einstein and Ehrenhaft's wife. Ignored by conventional Einstein biographies, this episode took place during the initial years of the Second World War, but was rooted in disputes dating back to the early years of the twentieth century. The interesting intersection of a series of scientific controversies also highlights some aspects of the personal dramas involved, and after so many years the whole affair in itself is still intriguing.