Holy smokes! I finished it!
Last night I finished the fourth Hazardous Tales book. Treaties, Trenches, Mood and Blood is the title. It covers the full length of WWI. This was the hardest Hazardous Tales book to complete. It is dense, dense, dense--so much information.
I think it is probably the least funny, but the most awesome book in the series so far. It'll be out in May, you'll have to tell me what you think. It can actually be pre-ordered at some online booksellers right now.