With the publication of the 1982 edition of Field Manual 100-5, Operations, the U.S. Army presented a fighting doctrine rooted in classical military theory. Yet, doctrine, to be useful, must be accepted and understood in its own right by those who have to apply it. Clausewitz's idea of the culminating point is a good example. FM 100-5 cites the concept of the culminating point as central to understanding Air-Land Battle and operational art and, consequently, explains it to its readers. The Clausewitzian concept of the culminating point is even more important to officers who plan and conduct theater operations. This book offers a critical analysis of the theory of the culminating point in the well known Gettysburg Campaign conducted by General Robert E. Lee in 1863. This Civil War battle has been the subject of more study and extensive written works than any other battle of the war and the student of military history would think that it would be rich in examples of the application of military theory, in this case the concept of the culminating point. Was the Clausewitzian theory of the culminating point evident in the campaign? Did Lee consider the concept and apply it to his decisions regarding the Campaign? Did the campaign support the concept and add validity to it? In looking for these answers, the reader can better understand the application of the concept of the culminating point, and, thereby, become a better practitioner of turning scientific theory into artful tactics and operations. Lee's 1863 campaign into Pennsylvania is an excellent case study from which to investigate many of Clausewitz's theories about war. The concept of the culminating point is particularly well served by what happened in the campaign. FM 100-5 has reintroduced the culminating point to the U.S. Army and has contributed to the educational process to help soldiers detect the culminating point with the "discriminative judgment" Clausewitz said was necessary. Studying campaigns like Gettysburg can be very useful for a better appreciation of theoretical and doctrinal concepts. A better understanding of theory and its relationship to doctrine is important; understanding the key concept of the culminating point is one example.