8.25X6 TLS in untranslated German signed in ballpoint ink at the conclusion by Karl-Friedrich Merten. Comes with a photograph of him.  In very good condition. 

(1905-1993) Karl-Friedrich Merten commanded the U-boat U-68 in Nazi Germany's Kriegsmarine during World War II. He received the Knight's Cross of the Iron Cross with Oak Leaves. Merten was credited with the sinking of 27 ships for a total of 170,151 gross register tons (GRT) of Allied shipping. Merten joined the Reichsmarine (navy of the Weimar Republic) in 1926. He served on the light cruisers Karlsruhe and Leipzig during the Spanish Civil War patrols.

He joined the U-Boat service on May 1, 1940. From October 1940 until January 1941 he joined U-38 as a trainee Captain with the experienced Heinrich Liebe.On 11 February 1941, Merten commissioned U-68 and lead 5 successful patrols. He operated all over the world, patrolling in the Atlantic Ocean, the Caribbean Sea and the Indian Ocean. U-68 was in the U-boat wolf pack Eisbär (Polar Bear Group), consisting of four submarines, U-68 (Merten), U-156 (Werner Hartenstein), U-172 (Carl Emmermann), U-504 (Hans-Georg Friedrich Poske) a fifth U-boat, U-159 (Helmut Witte) joined the group later, which in the course of a few weeks during September/October 1942, sank more than 100,000 GRT of shipping off South Africa.

On 22 September 1941 Merten torpedoed his first ship the 5,302 GRT British Steamer SS Silverbelle sailing in convoy SL-87 and on the 6 November 1942 he sunk his last ship the 8,034 GRT British Steamer SS City of Cairo. His total was 29 ships sunk at a tonnage of 170,151.

After this patrol Merten was appointed to the U-boat flotilla in Pillau, and this and other training appointments curtailed his operational career. Nevertheless, when the war ended he stood seventh in the table of U-Boat commanders in terms of tonnage sunk. After the war he made a new career (somewhat ironically) in shipbuilding, retiring in 1974.

Awards
Wehrmacht Long Service Award 4th Class (2 October 1936)
Olympic Games Decoration 2nd Class (21 December 1936)
Wehrmacht Long Service Award 3rd Class (2 October 1936)
Spanish Cross in Bronze (20 April 1938)
Sudetenland Medal (20 December 1939)
Iron Cross (1939)
2nd Class (2 October 1939)
1st Class (31 December 1941)
U-boat War Badge (1939) (2 August 1941)
with Diamonds (30 January 1943)
High Seas Fleet Badge (9 October 1942)
Knight's Cross of the Iron Cross with Oak Leaves
Knight's Cross on 13 June 1942 as Korvettenkapitän and commander of U-68
147th Oak Leaves on 16 November 1942 as Korvettenkapitän and commander of U-68
War Merit Cross 1st Class with Swords
2nd Class (30 January 1944)
1st Class (29 October 1944)

Comes with a full Letter of Authenticity from Todd Mueller Authentics.