Letter to Daud is a written note found in Dishonored.
Transcript[]
Daud,
I am satisfied. Corvo would have been very useful to me, but your improvisation was exemplary. Him taking the fall for the crime simplifies matters greatly. I hope your are equally satisfied with the payment.
I shall contact you shortly for additional assignments.
--H.B.
Location[]
It can be found inside a chest near Daud's bed, in the Chamber of Commerce building during the mission, The Flooded District.