''The Defence of Duffer's Drift''--written in 1904 by British Major-General [[http://en.wikipedia.org/wiki/Ernest_Dunlop_Swinton Ernest Dunlop Swinton]] under the pseudonym [[MeaningfulName Lt. Backsight Forethought]]--is a short book on military tactics set during UsefulNotes/TheSecondBoerWar. Over the FramingDevice of [[AllJustADream a sequence of six dreams]], Lieutenant Backsight Forethought, or BF, must defend a river crossing, the eponymous "Duffer's Drift", against a numerically superior force of Boers. The scenario [[GroundhogDayLoop starts out the same way over each dream]], and BF doesn't remember the terrain or the events each new time the scenario is replayed. What he does remember are a series of tactical lessons learned, which he applies to good effect in each new iteration. Eventually, his force does better and better until, on the sixth run-through, he manages to successfully defend the crossing.
The tactics that BF uses are [[TechnologyMarchesOn a little dated]] for today, but many of his observations on entrenching and [[GeoEffects terrain tactics]] are still valid. It is all-but-required reading in military academies today and spawned a series of FollowTheLeader works of varying quality, using the same dream format to examine logistics, procurement, and Second Iraq War counterinsurgencies.
In the Public Domain. Project Gutenberg's copy is available [[http://www.gutenberg.org/files/24842/24842-h/24842-h.htm here]].
!!This work contains the following tropes:
* BigBookOfWar: not that big at less than 200 pages, but otherwise fits the bill.
* BritsWithBattleships: Or in that case, Entrenching Tools.
* CombatPragmatist: the Boers are this, all the way; they start by infiltrating the British camp with civilians, and when BF learns not to trust civilians and to entrench, they pepper his freshly-built trenches with Nordenfeldt guns. BF himself develops from a fresh-faced new lieutenant into a combat pragmatist as things go along.
* DeployableCover: at the beginning, BF has no earthly idea what to do with the sandbags and entrenching tools he's been handed (over his protests), since to him warfare is about volley fire and bayonet drill, not about digging. He learns his lesson soon enough.
* EnsignNewbie: BF starts out as one, fresh from Britain, more concerned with parade-ground neatness than with proper tactics. He [[TakeALevelInBadass gets better]] as the book goes on.
* FollowTheLeader: The framing story became a popular concept in military manuals, and there were many imitators in many languages.
** [[http://regimentalrogue.com/boobysbluffs/booby0.htm The Battle of Booby's Bluffs]], a book on how to attack WWI-era trenches with an American infantry battalion and support units.
** [[http://regimentalrogue.com/bowler/bowler_bridge.htm The Defense of Bowler Bridge]], in which a British infantry platoon, circa 1930, defends a river crossing against armored cars.
** The Defense of Hill 781, in which the concept is translated to a late-20th-century American armored task force.
** [[http://defenseofjad.com/ The Defense of Jisra al-Doreaa]], written by two U.S. Army officers and taking place in Iraq during TheWarOnTerror.
* GeoEffects: the whole point of the book is how to use them effectively.
* GroundhogDayLoop: each dream is set the same way: defend Duffer's Drift against an unknown enemy force. It differs from the norm in that BF remembers nothing of the previous loop except for general tactical lessons learned to prevent him from "cheating" at the scenario.
* HaveAGayOldTime: A minor example, but when BF talks of 'guns', he explicitly refers to the Boers' cannon and Nordenfeldt guns, and not small arms (rifles, muskets or anything smaller).
** The term Kaffir, used to describe the black natives, is [[BerserkButton incredibly offensive]] in Africa nowadays. [[SocietyMarchesOn Back in 1904, however...]]
* HoldTheLine: The mission in all six dreams is "to hold Duffer's Drift at all costs," in the author's own words.
* ImagineSpot: Following the final, successful defense in the last dream, BF begins dreaming that his actions ended up being so decisive to the conduct of the whole war that he receives a knighthood--just before he's woken up for good.
* LemonyNarrator: BF's naivete at the start is so painful that he himself plays up his earnestness for comical effect.
* NicknamingTheEnemy: the Boers are referred to ironically as the "brothers" or the "brethren".
* RebelLeader: guess who the friendly farm-owner turns out to be? One of the first lessons learned: during times of guerilla warfare, do not trust strangers.
* UsefulNotes/TheSecondBoerWar: the setting.
* StupidEnoughToWork: BF finally wins in the sixth dream by throwing away the standard military advice of "hold the high ground" and entrenching in the riverbed itself--an idea that he dismissed as crazy nonsense when he first thought of it since it went against all of his conceptions of warfare. One of the key lessons learned is "a hill may not, after all, though it has 'command,' necessarily be the best place to hold".
** The Boers actually did entrench in a river at Magersfontein, to great success, which is probably where Swinton got the idea.
* WarIsGlorious: BF [[InvokedTrope invokes]] the trope early on, thinking of massed volley-fire and desperate bayonet clashes. The reality, of course, is very different, with long-range sniping and guerillas all around.
* YouCantThwartStageOne: BF's goal is to avert this through his GroundhogDayLoop. It still doesn't keep him suffering the full brunt of MurphysLaw every time he commits a mistake or disregards a vital tactical precaution. He puts up sentries and sends the rest to bed? The sentries get shot and the camp overrun. He orders the soldiers to stay alert? The Boers snipe them silly from all sides. He has them dig in? The Boers produce ''cannon and Nordenfeldt guns'' on the hills. He has them dig in and propery fortify on a nearby hilltop? The Boers [[AntiClimax simply ride through the drift past them]], taking advantage of their self-inficted immobility.