Fire and water, two of the earth's elements that are crucial for the survival of its inhabitants, are also weapons that have been used since ancient times to wage war. China made use of fire and water well before its 14th-century discovery of gunpowder, which revolutionized the way wars were fought, particularly once Europeans imported it.

Ralph D. Sawyer, the author of this remarkable and well-documented book, says that fire can have an unimaginable impact and is the weapon of choice for poor armies as well as those that are outnumbered by more powerful armies.

Fire also plays a purifying role, and is a fundamental element in religious and cultural myths and in meditative techniques. It is commonly used in cooking, lighting, heating and numerous other ways by human beings to improve their living conditions.

Sawyer traces incendiary warfare through the Chinese text known as the Spring and Autumn Annals at around 705 BC when fire was used in the state of Lu. It was believed that the state of Lu was the first to use fire in warfare and the well-known Chinese war tactician Sun-tzu related it in his classic Art of War book, which is still being studied in military academies in China.

Military commanders in the widely-read history book Three Kingdoms try to perfect the use of fire depending on the day of the month, wind directions, dry and wet seasons, conditions of the terrain, and so on. They also develop five situations in which fire can be used.

Sun-tzu's Art of War says, "Thus using fire to aid an attack is enlightened, using water to assist an attack is powerful. Water can be used to sever, but cannot be employed to seize."

Sawyer interprets Sun-Tzu as saying that incendiary warfare techniques are effective and therefore its employment is enlightened because there would be no apparent need for frontal attacks. Following his reasoning, water can be used to inundate and isolate an enemy, but fire can be used to seize the enemy's position quickly.

The study of fire and water warfare goes through the Warring States period in China, but the first systematic use of incendiary warfare for strategic purposes was recorded under the Han dynasty. Sawyer gives precise details of how wars were waged among the commanders during that long period.

The author provides several illustrations about the methods, weapons and techniques used in incendiary warfare, including using horse-drawn or push carts containing burning wood or oil, oxen carrying spears and fire, birds used to spread fire, and arrows carrying gunpowder explosives.

Fire is fanned by the wind, and so wind is carefully studied by Chinese military theorists in order to make the use of fire more effective. One 17th-century text clearly states "In employing incendiary attacks, wind provides the power. In strong winds, the fire will be fierce. When the fire is intense, wind will be produced. When wind and fire mutually pulse each other, you can seize victory." An illustration in the book shows a machine creating wind to help fan the fire. Smoke, of course, can be used as a defensive tool. But military commanders know that they cannot always control smoke.

China has a surplus of water in some parts of its vast country, but in other parts the soil is arid year round. The struggle to contain water in the regions with a surplus of water dates back to the period extending from 2000 BC to 1600 BC, and it continues to this day.

A famous Tao Te Ching verse says, "Under Heaven there is nothing more pliant and weak than water, but for attacking the firm and strong nothing surpasses it, nothing can be exchanged for it."

Like fire, the use of water in warfare is widely reported in China's military books. Not only is water used to flood an enemy's stronghold or camp, but it also can be used to spread poison. Water is used to fight fire, a weapon against another weapon. Finally, water, like fire, is a source of life, not just a weapon.