It depends with respect to what specifically.

• I'd consider Hew Strachan's The First World War: To Arms for as an intermediate work on the 'starting positions' of everyone. It's absolutely thick (something about 1300 pages I recall) and covers literally everything from Austria-Hungary to the shell shortages and everything you can imagine.

• I'd certainly consider Robert Massie's work Dreadnought for the naval realm of things, however, I'll wait for /u/an_ironic_username to weigh in as his other work, Castles of Steel, may be more appropriate (I have yet to read that one).

• Holger Herwig's The Marne: The Opening of World War I is a great introductory book but I'm still putting it here as it's packed with a stupid amount of sheer information. Everything from what infantry divisions fought where, how much of X everyone had going into what. It's not so much rivet counting (as I feared going into it) but it just leaves no stone unturned. If you just want a wave of just pure military knowledge for August - October 1914 this is it.

• Holger Herwig's other work, Germany And Austria Hungary 1914-1918, is just a great general history. It involves military history stuff (obviously) but it's very much in depth about everything that happened in the homefronts and in their political systems throughout.

• If you want to know about trench life Hot Blood and Cold Steel: Life in the British Trenches in the First World War by Andy Simpson is not so much 'intermediate' (it's just a collection of firsthand accounts with some pretty elementary analysis) but it's still invaluable in my opinion. Certainly pick it up. If you want a bit of a more in depth work (but significantly less focus on firsthand account) Tommy: The British Soldier on the Western Front 1914-1918 by Richard Holmes is your best bet.

Yes it's more than 3 but this is as far as I could narrow it :P

"A World Undone"

• A well researched, documented, and detailed book that starts with the causes of the war, gives background on events and key players, and step by step goes through the major events from both the Central Powers and Entente. It's the best all around WWI book I've found, highly recommend.

"The Guns of August" It gives a great detailed history of pre war settings as well as in depth analysis of the fighting.

I'm in the middle of Dan Carlin's Hardcore History: Blueprint for Armageddon podcast.

Does anyone know how legit it is? Or how legit Carlin is?

This podcast, and all of his others, are truly fascinating. He is a great raconteur.

Follow up question. Any recommendations on books specific to WWI aviation?

I am currently in the middle of Now it Can Be Told by Phillip Gibbs. He was a battlefield reporter that wired back his stories to the papers in London, which were heavily censored and redacted before publishing. (The book was written after the war, hence the title)

It gives (to me) a very stark, unwashed view of the day to day of the line soldiers and lower level officers, and does not hold back one bit on the horrors the Tommies faced. Not much on overall strategy, but concentrates on the individual stories and anecdotes about life in Flanders during the war.

I just brought The Rise and Downfall of Prussia: 1600-1947 and The Sleepwalkers: How Europe Went to War in 1914 by Christopher Clark. I've gotten reccomendations to read them, but haven't gotten around to actually reading them due to work. :/

I'd also recommend The End of the European Era: 1890 to present by FElix Gilbert and David Clay Large which is an awesome encompassing overall history book

"the war that ended peace"

"catastrophe 1914"