During his life, the teaching of the Buddha was passed on by reciting word for word what he had spoken in his teaching. These were called the sutras, and always began with "thus have I heard". They are a collection of sermons, poems and often include stories to provide a message.
These sutras were meant by him to lead us to understanding but at the same time, not for us to depend on any doctrine, even the words spoken by him. The Buddha teaches us to understand more how to live, than why we are here. The sutras are practical and provide methods to enable us to reach that understanding.
Hundreds of years later, these sutras were written down, and form the basis of much of todays understanding of Buddhism. Obviously, like other old and revered texts, there is continuous debate about the meaning, and the input from the many different transcribers of these verbal teachings.
One of the most popular sutra is the Lotus Sutra, which was one of the teachings close to the end of his life. The lotus is a recurring symbol in Buddhism and represents the enlightened person, starting like a lotus flower, with roots in the mud, growing through the water to finally see the daylight at the top of the water.
The Lotus Sutra is particularly influential in Japan where some followers embrace this teaching often by chanting whole sections. The Lotus Sutra promises salvation for all beings, and gives the message that everyone is able to reach the Buddha mind.
There is a huge amount of information in the sutras, and there are now many authors who present the parts of the sutras in a clear and simple way to be understood by most Western readers. The famous Vietnamese peace activist Thich Nhat Hanh has written several books explaining the sutras. These include " Thundering Silence" , " The Heart of Understanding" on the popular Heart sutra, " Transformation & Healing" , and " Our Appointment With Life" .