I just became a member of the World War One Historical Association.  What I didn't expect was their book section, which is filled with titles and subjects that are new to me.  I don't think you have to be a member to purchase any of these.  All I know is that many of the titles look extremely interesting and I will definitely be ordering some.

 

EDIT: Apparently you don't purchase them directly on their site, but there is a "Goodreads" link for each one, which leads to another site where you can get them by PDF download, or links to Amazon, etc.

 

Right now I just chose to be a member level that sends you a printed copy for USA members.  In the future, I might might consider going to the "Donor" level, mainly to support an organization who's interests are so in line with my own.

 

In any case, I hope you find something here that you're interested in, and haven't found before:

 

WW1 Books

This looks like a very cool organization.  I'll definitely check them out.

A couple years ago I came across a book on a discount shelf at a convenience store that was in fair shape. It was called Full Circle and detailed the mistaken assumptions made by upper commands between the First and Second World Wars as well as between Korea and Vietnam. It was a damn good read and still resides in my library.

The link in the O.P. above (now edited) is just books you could get through "Goodreads" linked from their site.  There is an historian associated with their organization, who is now deceased, named Ambassador Len Shurtleff.  You'll see references to him prominently on their site, and here's a link to his WWI introductory favorites:

 

Shurtleff's Favorites