It's a wehrpass--a document all German men were issued it after they registered for the military. Active duty military men wouldn't have that with them--they'd have a military document instead. This guy's name looks to me to be Emil Albert Gmelin and there's a stamp on there that says "Mosbach", which is a city in Germany near Heidelberg, and that's where he registered, at the wehrmeldeamt (military registration office) on Oct. 21, 1938. He was born December 3, 1911. Looks like his mother was Luise Muller Gemelin, and his father was Emil Gmelin. He had 2 children. His nationality was German.

that is so cool, thank you everyone for the responses!!