Score

I'm wondering why A Farewell To Arms, Birdsong, A Very Long Engagement and Storm Of Steel are not on this list.

Because Birdsong isn't very good, and I haven't read the others, but feel free to add them yourself.

Birdssong isn't very good? Hmmm. And why do you feel that way? Granted it is not as strong as A Very Long Engagemnet, A Farewell To Arms, Storm Of Steel but I found it quite good. Much better than his other war novel Charlotte Gray.
I would add To The Last Man by Jeff Shaara but although I found the book interesting I find that Shaara has a problem with unrealistic dialogue. If you have ever spent time in the military or on a sports team or with a group of men you would know that the dialogue can be quite colorful. Shaara's inability to use profanity in his books takes much of the realism out of the characters. I don't know if he is trying to reach a younger audience or does not want to offend the Puritians in his readership but the "Ah shucks" dialogue just doesn't ring true in war. Read G. F. Borden to get a true picture of combat conditions. Neverthe less, All Quiet On The Western Front is probably the best war (anti-war) novel ever writen. That coming from a Hemingway scholar but A Farewell To Arms pales next to All Quiet. I'd post those books but I'm new to this and have no idea how. I was very happy to see you include Wilfred Owen, Robert Graves, Vera Brittian and Erich Maria Remarque. Thanks for your input. We agree to disagree. Mike

The 'add books' button is on the top right, just above the bit where you vote.
I don't dislike Birdsong, it just didn't like it either and really don't consider it to be one of the best world war 1 novels. Hence two stars on Goodreads and I didn't personally add it to this list. But I accept that a lot of people think it's ace, so by all means add it.
My favourite is Under Fire, incidentally, but it's not a very well-known one.

Do autobiographies, like Testament of Youth and Goodbye to All That, belong on this list? Granted, people have claimed that Robert Graves used a lot of artistic licence in his.

Yes.

Just because something is true, doesn't mean it isn't literature.

A good list, but the list author stated "plays, novels and poetry." Readers appear to have ignored that aspect. I see Tuchman, Brittain, Eksteins, Fussell, T.E. Lawrence and others who wrote memoirs or works of non-fiction. Why spoil a good list?

Abi: you want the non-fiction off the list?

Note: "Memoirs of an Infantry Officer" by Siegfried Sassoon is, actually, a novel.

I don't remember Isabel Colgate's The Shooting Party (currently #104) being a novel "written about the First World War"...?

Checked for duplicates: 1 book removed.

Checked for duplicates: 2 books removed.

This says "Plays, novels or poetry" but there's a lot of non-fiction here. I mean, Goodbye to All That is at number 4. I think they should either be removed, or the description should be changed – don't particularly care which but it's very confusing right now what should be added.

Warwick wrote: "This says "Plays, novels or poetry" but there's a lot of non-fiction here. I mean, Goodbye to All That is at number 4. I think they should either be removed, or the description should be changed – ..."

Apparently, some readers are so intent on adding to GR lists that they ignore the lists' criteria. Or perhaps they don't understand the difference between fiction and nonfiction?