I've read a lot of great books about World War One - and this is the best.
In a mere 200 or so pages, Erich Maria Remarque perfectly captures the absurdity, tragedy, humour, horror, camaraderie and waste of war. This book packs so much in, and it is beautifully and simply written.
A room full of German schoolboys, in 1914, fresh-faced and idealistic, are goaded by their teacher into enlisting for Germany's glorious war, where inevitably the young boys become old men in a matter of months. No one back at home can ever understand the horror of this new mechanised style of warfare and quickly the boys, robbed of their lives and their youth, realise they only have each other. Inevitably, one by one the boys die or get injured.
Erich Maria Remarque touches on many aspects of the conflict: the violence, the terror, the politics, the home front, the pettiness, and so on.
If you only have time to read one book about World War One then read this. It's stunning.