When someone seeks to understand Buddhism, where should that person start? With the meaning of taking refuge in the three jewels? With the four noble truths? The Dalai Lama, when asked this question, suggested that for many in the West today, understanding the two truths—conventional truth and ultimate truth—is the best place to start. When the Buddha awoke from the dream we still dream, he saw the ultimate reality of things just as they are. There are shifting appearances and conventions, the manners and traditions of the vast and diverse world; and then there is the mystery of the sheer reality of things. And yet we cannot find this reality anywhere else but right here. Each system of Buddhist philosophy has its own way of explaining exactly what these two truths are and how they relate to one another. In exploring these systems, we are looking over the shoulders of Buddhist thinkers as they grapple with a basic question: 'What is real?' This is not an idle intellectual exercise but a matter which cuts to the heart of our practice in life.