I've enjoyed reading books about US submarine ops in WW II. They would frequently mention using these manuals and that made me want to get some. I'm very pleased to have these!
Not directly model related but interesting nevertheless. Some of you know what a "ONI 208-J" is but for the unlearned among you (LOL) they were recognition manuals the US Navy used in WW II to enable our forces to ID Japanese merchant ships. I'm fortunate enough to have two in my collections. The top one is from 1942 and the bottom one is from 1944.