On War was written by a Prussian general, Carl von Clausewitz, between approximately 1816 and 1818. It is regarded as one of the most important documents for the study of the nature, strategy and theory of War.

The book covers eight volumes:

    1.    On the Nature of War.  This volume sets out the theories that form the framework for subsequent volumes, and includes information on some of the most basic Clausewitzian models.

    2.    On the Theory of War.  This volume consolidates the basic theory in the previous volume, and develops some specific theories on the science behind War. He also includes a chapter on historical evidence to back up his theories.

    3.    On Strategy in General.  This is considered the real "meat" of the book, and its lessons have been employed by many great military leaders (Montgomery, Patton, Rommel and Colin Powell all studied Clausewitz and followed his advice).

    4.    The Engagement. Covering all of the elements of the engagement from political inception to the initial battle, this volume is essential reading for anyone interested in the dynamic effects that end up leading to War.

    5.    Military Forces.  In this volume Clausewitz describes how an Army should be formed, administered, trained and led. Some of the lessons are evident today in the running of some of the world's most powerful military forces.

    6.    Defence.  The largest volume in the book, this concerns the importance of being able to defend oneself against hostile action in order to be able to prosecute the campaign more effectively.

    7.    The Attack.  Having considered all of the essential base elements of War, Clausewitz now proposes strategy and tactics for fighting battles in specific theatres such as encampments, mountains, rivers and fortresses. He also covers some of the theory behind the success of such strategies and tactics.

    8.    War PlansClausewitz finally writes about the importance of preparing for war well in advance.

On War is essential reading for anyone interested in the theory of War, and, as I have intimated, is also of great use to military commanders and planners. It can also be applied to other situations; there is a lucrative trade at the moment in books applying Clausewitz's theories to politics and business.