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A Brass Hat in No Man's Land by F.P. Crozier
one of the most famous memoirs of World War I.
https://www.amazon.com/dp/B01CD0KNVU/
https://www.amazon.co.uk/dp/B01CD0KNVU/
https://www.amazon.ca/dp/B01CD0KNVU/
"Nothing of Importance", Eight Months at the Front with a Welsh Battalion by Bernard Adams
incredible description of trench warfare.
https://www.amazon.com/dp/B01CD19WFM/
https://www.amazon.co.uk/dp/B01CD19WFM/
https://www.amazon.ca/dp/B01CD19WFM/