It's translated by Udon from the Japanese edition 戦場のヴァルキュリア3 COMPLETE ARTWORKS that was published in 2011. There are 256 pages in this paperback.
It's basically the concept art book and visual guide for the game. There are illustrations for characters, weapons, vehicles, scenes, storyboards, a bit of environment art and other promotional materials.
Character designs still form the main bulk of the book. There are sketches and many variations to look at. Some characters are from the previous games. For a military establishment, the military uniforms are as non-standardised as they can get. Even so, with a common art direction, you still see that they are from the same army.
What might interest fans would be the extensive commentary provided by the design notes, character profiles and story summaries.
It seems that the game wasn't released in English. If don't know Japanese and can't play the PSP game but still want to follow the series, then this art book will be great for you.
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