Sutras are the teachings of the Buddha. They vary widely in style, content and approach, and may seem to be different philosophies, but there is a central unifying truth in all of them. Buddha was an expert teacher and believed we should teach people with different abilities and inclinations in different ways, while never straying away from the central principle. Traditional Buddhists treat books on the Dharma as sacred, hence it is considered disrespectful to place them in a low position, read them while lying down, or place them where they might be damaged by food and drinks.