This one isn't a graphic novel, but it has a lot of graphics and comics in it, so I will keep it on the graphic shelf.
I tend to really like "Horrible Histories" and pretty much anything Terry Deary does, though the humor is often groan-worthy.
This book is great. It's easy to read and gives the reader a sense of how the war started; how it ended; how it affected the lives of civilians as well as soldiers, young and old, men and women, and to a certain degree wealthy and poor; it makes pretty vivid the hunger and discomfort so many suffered and the outlandish propaganda that kept people fearing the 'other side'; there are stories about mice, lice and other vermin and the flu that took more lives than the war. Some of the stuff I found most disturbing was about the shootings of soldiers by their own armies as punishment for abandoning their post (and regardless of the circumstances). I enjoyed reading about the homing pigeons and about women's participation in battle.
In the book are included: rhymes, slang and sayings of the time; first hand accounts; timelines; bios of various people and other animals; comics; historical commentary. It's a solid and entertaining introduction to the war for middle graders and a nice book for adults, too. Sometimes maybe it tries to hard to entertain, but that's sort of what the series is all about.
Here's a bit of slang from one of the comics in the book. Readers have a chance to work out the meaning before reading a translation. "I'd love a bon baby's head, followed by a dog and maggot, washed down with gunfire..."
Translation: I'd love some nice meat pudding followed by bread and cheese, washed down with a cup of strong tea..."