"A general and soldiers who seek refuge behind lines are already half conquered..."
This single title contains a collection of three of the most influential military treatises ever written; and Machiavelli's odd dialog, which is written like a Socratic play. Sun Tsu, Clausewitz, and Jomini make excellent reading, and are intriguing. Together, they make this book a substantial choice for your money, as it is probably the best way to buy these titles. Whether you are the military type or not, you will find much here to interest you. These books, like Machiavelli's better known work, The Prince, teach principles of strategy and planning that can be seen as inspiring in all areas of life.
I already own and have read Sun Tsu's The Art of War in hardback. It was written in the Fifth Century BC in China, and is much like a collection of proverbs and pithy sayings. His work is intensely readable, and easily absorbed, like a smooth tasting Oolong Tea.
Machiavelli's book is quiet complex in format, and contains archaic spelling that makes it challenging to read. He lived at the turn of the Sixteenth Century during the Italian Renaissance. I'd read his better known book, The Prince years before and found it relevant enough. It's just that as a philosopher, he's a bit off the deep end of human relations. If one takes the American General Sherman's viewpoint that 'War is Hell!' then one could believe that Machiavelli was the devil himself. He advocates a rather cutthroat philosophy that lacks any of the wine of honor that men usually wash their war instincts down with.
Clausewitz and Jomini wrote their treatises after Napoleon's Wars. Jomini's viewpoint was that of a Staff Officer and theorist. He was born in Vaud, Switzerland in 1779, and Clausewitz the following year in Berg, Prussia. Jomini was a Swiss in the French army and later in the service of Russia, so he was something of an outsider. Clausewitz had access to officer’s status at the beginning of his career that led all the way to General. While Jomini's work is more of the 'black coffee' practical type; Clausewitz was more of an abstract thinker who provided a broad unifying vision to warfare that just keeps on giving in any age.
Jomini’s ideas were simple: put superior combat power at the decisive point. He wrote his work as a field manual intended to be taken into battle as a practical application guide. His ideas were intensely popular at first, but since warfare changed from that of cavalry and lance, to that of mortars and trenches, his hasn't aged as well as Clausewitz's principles of 'Das ding an sich' or 'the thing in itself' of the phenomenon of war. Clausewitz's ideas seem more relevant today, for those reasons.
The major difference was that Jomini focused far more on the art and mechanics of battle tactics. He offered a formulaic approach, through the use of geometric terminology, for example. While Jomini himself claimed that military strategy is an art rather than an exact science, he uses many scientific and mathematical principles to illustrate his points.
Clausewitz focuses more on universal elements of human psychology, Clausewitz's work is timeless. His was much more focused on the psychological dynamics of war. He was a much more abstract thinker than Jomini, and subordinated specific techniques and tactical approaches to an understanding of the forces that a general had to deal with both internally and externally in battle.
I first became aware of some of Clausewitz and Jomini's ideas several years back through some of the strategy video games I play. I think that most players of the Civilization series, for example, are familiar with these ideas in practice. I read a bit more about them in Olan Thorensen's Destiny's Crucible series, where he mentions them a few times. But, I'd read neither book. I was glad to find this Kindle collection in order to compare the writings in one big read.