The West Point Atlas of War: World War I.
This is the Great War researcher’s go-to source when the maps in a book don’t deliver.
A large-format book, it needs a generously-sized desk or table to accommodate its width and depth when opened. There’s a legend inside the front cover defining the symbols that are used. The atlas is printed on heavy-duty buff colored stock, using a limited number of colors to designate units and troop movements. Each map is accompanied by a single-page summary of the action depicted. The printing is of excellent quality, although I think it’s easier to read in bright natural light than under artificial light.
Much of the same information is available in free map downloads from the West Point Department of History website, and there are some advantages to that, but I think it’s worthwhile to have a clear print copy to pore over at my leisure, without eyestrain from staring at a screen. Highly recommended.