The letter is in the form of a V-Mail communication. As of 4/10/2018, Wikipedia describes V-Mail as follows:
"V-mail, short for Victory Mail, was a hybrid mail process used by the United States during the Second World War as the primary and secure method to correspond with soldiers stationed abroad. To reduce the cost of transferring an original letter through the military postal system, a V-mail letter would be censored, copied to film, and printed back to paper upon arrival at its destination. The V-mail process is based on the earlier British Airgraph process."
Neimans' address listed as:
1004 Lincoln Pl.
Boulder Colorado
Return address listed as:
Prt. D. P. Wodianshi 38502587
GE 407 Inf APO 102
c/o PM N.Y.N.Y.