•Why it earns a slot
Why it earns a slot: Brooke wrote these five war sonnets in late 1914 and was dead of sepsis by April 1915, so a book that opens by thanking God for war reads less like propaganda and more like a man writing his own epitaph in advance.
Rupert Brooke wrote five sonnets welcoming war as a cure for boredom, then died of blood poisoning before he ever reached a battlefield.
This distillation is written from the freely available original, which is always the better read when you have the time: Project Gutenberg.