hello I recently sold a large Third Reich signature collection. Raeder and Donitz are slow movers in the autograph department. Post war signatures are plentiful and abound, more so for Donitz as he lived until 12/25/1980 and signed much. Raeder died not too soon after the correspondence that you have, in 1960, if memory serves me correctly. Post war Raeder signatures are about $150 to $200 tops......dependent upon the content of your letter that may make it more desirable but not necessarily more valuable cheers, Ryan