Ernest Dunlop Swinton is a military professional with experience in the Boer War who wrote this famous short book based on a series of thoughts he had on how an infantry unit with only 50 men could defend a river crossing. Through the perspective of a young Lieutenant, you are given the terrain features, the political situation, conflict with civilians and limits on your own military support. There is a brief history of the war with the "Dutch" and then your Lieutenant receives his assignment. With the use of maps, there are six scenarios of the Lieutenants approach to defending the crossing (drift). Each scenario is acted out and with each of the first five scenarios there are several lessons learned such as the effect of enfilading fire, the limitations of a simple trench, the use of the military crest versus being located on top of the hill, the effect the local sympathetic population may have on aiding guerrilla fighters, the effect of surprise, disguising your defense from view, proper posting of sentries and responsibilities, how to combat artillery, dealing with multiple directions of attack, using the terrain to advantage and on. As the Lieutenant in each scenario learns from his mistakes, he alters the outcome to his advantage but only incrementally. Only at the end and sixth scenario does he get it right but with realistic loss. The same map is introduced in each scenario with defense features matching the new defensive tactics. "The Defence of Duffer's Drift" is a fascinating book for all interested in basic infantry tactics, which has been used as a training manual for militaries worldwide. This is a very readable book that can be read in less than 2 hours time. Applicable to any war but this book would be interesting to read with an account of Rappahannock Station, which was a spearhead position held by Confederates in advance of Lee's line on November 7, 1863 where Meade's forces overwhelmed the defenders and took almost 3,000 prisoners. Duffer's Drift would be very applicable in that situation.