Quotation out of the book:
One looks for it and sees it not,
it is called: invisible.
One listens for it and hears it not,
it is called: inaudible.
One reaches for it and grasps it not,
it is called: intangible.
These three, not examinable through reasoning,
interwoven with one another they are one.
Its upper is not light,
its lower is not dark.
Ceaselessly onwards it flows,
and returns to the being-less.
That is: of the formless form,
of the imageless image.
That is: the most unfathomable of the unfathomable.
One approaches it and sees not its beginning.
One follows it and sees not its end.
When the Tao of the forefathers is preserved,
to guide the essence of today,
from time immortal one can Know.
This is called: endless unfolding of the Tao.