My "Appendix N" would actually be more an Appendix Historia. I find history and historical fiction far more interesting as a draw and basis for creating fantasy adventures instead of say a Robert Jordan novel. That's not a slight against Mr. Jordan (God rest his soul) but more a statement about how I think fantasy novels can negatively influence your own adventures. In other words, what you create will be in some way a pastiche of the fantasy work you were influenced by. Contrast that to taking a historical event and adding a bit of the fantastic into it. To me, this creates a solid grounding which is a pigeon hole that players can become comfortable in, then you leak in the fantastic and up the ante. The Song of Fire and Ice series (Game of Thrones, etc.) has its genesis from the War of the Roses..but with a lot of fantasy tweaking.
So let's take the French & Indian War as we called the 7 years war here in the colonies. In essence there were numerous raids back & forth by small bands and a few major engagements around forts and cities. The majority of the conflicts were small forces raiding and harassing one another. I used this as a basis for long campaign where two human kingdoms were at war between the edges of their colonies. The players were all "colonists" caught in between and tasked with defending their little village. Eventually they are raided...by a mixed force of humans...and elves! Yup the elves played a "neutral" force and many trials and misfortunes rested upon the ability to convince elves to stay on the player's side. Then other fantastic elements would appear, caverns, wendigo, giants, ogres, undead. The deeper they explored and the worse the war became the worse the fantastic element that was unleashed...but it never became a "monster of the week" sort of thing.
Anyway, my point is from a historical event I was able to slowly build a campaign that didn't rely on monster of the week, nor a deeper dungeon level, nor "more magic" to create excitement. The historical events were already proven tense and interesting, I just had to tweak them a bit and had the joy of adding a little more fantasy wow factor when I needed to!
So this summer I have embarked on a massive summer re-reading of some classics that form the core of the Appendix Historia for HOW.
Herodotus, The Histories
Thucydides, History of the Peloponnisian War
Livy, The War with Hannibal
Arrian, The Campaigns of Alexander
Xenophon, The Persian Expedition
I have a laundry list of more history, a lot of great books from historians like Adrian Goldsworthy, John Keegan, Donald Kagan and Victor Davis Hanson, as well as great historical fiction to recommend as well...but finishing Cauldron #1 and making it available this Saturday is probably of more immediate interest.
The work continues...