You may have noticed that, on some very basic level, mindfulness is pretty much the answer to everything. This happened over and over again until finally I realized that it was the practice of mindfulness, and not the particular experience, that was important. That is, to free the mind from bondage to the forces of greed, hatred and delusion. He then goes on to explain that mindfulness is the beginning, middle and end of the path to knowing, shaping and freeing the mind. Mindfulness is the key to knowing the mind, and so it's the starting point.
Mindfulness is the perfect tool for shaping the mind, and so it's the focal point.
And mindfulness is the manifestation of the achieved freedom of mind, and so it's the culmination point. When I read this I felt really happy. I love it because it's such a holistic viewpoint. In any moment of mindfulness, we have the beginning, middle and end of the path. It makes me appreciate those moments even more.