Wurmb, Eckart, Verlag EisenSchmidt, Berlin 1914. (German)

A fantastic wealth of information. Major Menzel became imaginary but was originally he was just listed as Max Menzel a first lieutenant in infantry Regiment number 58.  Eventually he just became a brand name like Aunt Jemimah.  Yearly for each service year they produced a handbook under the eye of the German Officer's club and sold it to families of incoming recruits. By the start of the war of the circulation was 400,000.

Everything you needed to know to be a soldier. Ranks, uniforms, heads of minor states, formations and drills, weapon care. You name it. pictures, text, diagrams.  176 pages and 10 color sheets.  There is also a WONDERFUL foldout map in the back with corps boundaries. Tactics, navigation, Morse code, marksmanship and much much more. Not only were these produced annually,but they were also produced for the different contingents. Soft cover.  Go for less than $60. Double or triple that on eBay.

There are many versions of the book. The 1914 one with 10 color plates is good.  For some reason 1908 is sought after.  Late 1914 and 1915 are poorer.