This is a book or magazine about tanks/AFVs and/or military modeling.
Ground Power magazine is primarily a pictorial, with very little in the way of anything that could be described as an article. Each issue, which generally focuses on 2-4 different themes, is 148 pages of primarily b/w WWII photos, one or two to a page with Japanese captions. These features can run for several issues, hence the "#2" or other numbers following some story names below. If you know what you are looking at, these are extremely valuable reference books. If you don't, the lack of English captions makes things a bit difficult.
This issue covers the German PzKpfw (2) and the organization of Japanese Armored Units (5).