Not a book, but a true story from WW2:

5 May 1945 Troops of the 23rd Tank Battalion of the 12th Armored Division of the US XXI Corps led by Lieut. John C. “Jack” Lee, Jr., a number of Wehrmacht soldiers led by Major Josef “Sepp” Gangl, SS-Hauptsturmführer Kurt-Siegfried Schrader, and recently freed French prisoners of war defended Castle Itter against an attacking force from the 17th SS Panzergrenadier Division until relief from the American 142nd Infantry Regiment of the 36th Division of XXI Corps arrived.

https://en.wikipedia.org/wiki/Battle_of_Castle_Itter?wprov=sfla1

Welcome Comrade! Advance behind this man. When he is shot, pick up his rifle and continue!

I heard that Linus named it git because he is one.