Here is a favorite piece in my collection. It is a letter written on-board U-564 by Teddy Suhren to his friend, Hans Geissler, Kmdt of U-440. The letter was written on May 25, 1942 as U-564 was returning home from her successful 6th war patrol. This was the patrol where the Mexican tanker Potrero del Llano was sunk, leading to Mexico to declare war on Germany. This was also the patrol prior to the PK photographing the 7th patrol that ultimately was the basis for Lawrence Patterson's book "U-Boat War Patrol: The Hidden Photographic Diary of U-564". The letter is 4 pages long and, to quote Detlev Niemann's description, contains "very interesting and personal contents...now on the way back from 2nd enemy cruise this year...how is your boat doing...be careful on your cruise...don't overextend and overrate your ambitions...always follow your feelings...I wish I could give you some of my experience...your Teddy". The original feldpost envelope came with the letter, as well as a post-war (1948) letter to Geissler where Teddy complains about his health.