Here are the letters between Nelly Sachs (1891 - 1970), recipient of the 1966 Nobel Prize for Literature, and the great German-speaking poet Paul Celan (1920 - 1970). Their correspondence lasted from 1954 until Celan's death by suicide. Sachs died the day Celan was buried.
From the Book:
"Divide yourself night
both your irradiated wings
tremble with horror
for I will go
and bring you back the bloody evening"
-- from Nelly Sachs's last letter to Paul Celan