The Lord of the Rings. J.R.R. Tolkien. This is simply the most enjoyable story I have ever read. Indeed, I have read it several times. Don't be fooled by the fantasy genre into thinking that it is not a serious work. In fact, I think this genre allows Tolkien to explore many deep themes, such as life and death, and the nature of good and evil. An excellent storyteller and expert linguist, Tolkien creates a world that feels so real that you'd swear it must really exist somewhere. The Hobbit and The Silmarillion round out this masterpiece.
The Guns of August. Barbara Tuchman. I never thought reading about the First World War would be that interesting, but Tuchman's account of the first month of conflict is absolutely gripping. No wonder it won the Pulitzer Prize.
The Franco-Prussian War. Michael Howard. It turns out that this conflict is quite interesting to read about too. It's a forgotten period of history. Howard sometimes quotes in French and German without translation, particularly in the footnotes, which can be tough if you don't speak those languages, but that's a relatively small quibble.
Lucifer's Hammer. Larry Niven and Jerry Pournelle. This is a science fiction novel about a comet striking the earth, and the aftermath. I couldn't put it down.
The Boer War. Thomas Pakenham. The British Army got quite a wake up call just a few short years before World War I. This is yet another little-known conflict that is fascinating in its own right.
Mila 18. Leon Uris. This novel takes you to the Warsaw Ghetto to experience the uprising against the Nazis. It was so compelling that I had dreams that I was in the resistance and was being hunted down in my bunker by Nazis with flamethrowers. It's just a great book.
Rabble in Arms. Kenneth Roberts. The American Revolution is the setting of this exciting historical novel, culminating in the battle of Saratoga. I have read several of Roberts' novels, and enjoyed every one of them, but this one had the most action.
The Rise and Fall of the Third Reich. William L. Shirer. If you only read one book about the European Theater of World War II, this should be it. It's a great look at the military and political leaders, their decisions, and the consequences of them.
Ender's Game. Orson Scott Card. This science fiction story follows a child prodigy as he learns tactics and strategy from the ground up.
The Long Knife. James Alexander Thom. I was fascinated by this fictionalized account of a true episode in American history, wherein an American officer, George Rogers Clark, leads a band of volunteers deep into the backwoods of the (then) American West to defeat British outposts in Missouri, Kentucky, and Indiana. Clark's younger brother William will be better known to most folks. He was the Clark of the Lewis and Clark expedition.
Fatherland. Robert Harris. The setting is 1964, but the Germans have won World War II and reach a sort of Cold War status with the United States, while continuing to fight a protracted guerrilla war in the East against what is left of the Soviet Union. A disillusioned SS police detective who served on a u-boat during the war becomes involved with a young American journalist while trying to solve the murder of an important German official. Steve Zoraster has written a more complete review.
