The Otto Nathan correspondence chiefly with Helen Dukas collection is comprised of eight handwritten letters in German dating from July and August of 1955, just months after the death of Albert Einstein that April. The letters were sent from European locations (Bern, London, Paris, and Zürich). Six of the letters are addressed exclusively to Helen Dukas and the remaining two letters are addressed to both Helen Dukas and Margot Einstein. As co-trustees of Albert Einstein's literary estate, Otto Nathan and Helen Dukas worked closely together following Albert Einstein's death.