Behind concrete Volition, Intellection, and Action, are the silent, ceaseless, inner and incalculable workings of innumerable brain-cells concerned with the mysterious constitution and metabolism of Life, and its strange, potent relation and correlation with Mind and with environment; concerned with character and attribute and impulse; with ancestral vestiges and personal experience; with memories and instincts; with an infinitude of occulted and imperishable records of previous terrestrial existences, perhaps; concerned, in a word, with all the secret springs and complex potences of Individuality; which differentiates every thought, emotion and action of any human person from those of every other. And in these recondite mysteries fructifying in a hundred million bi-sexual brain-cells, it may be that the subtle counter and inter-operations of the Man and Woman-traits find their highest activities, and make for their supremest issues. Every man and woman is to every other a Sealed Book, whereof no more than a few pages have been glimpsed--even by those nearest and dearest. We are Sealed Books to ourselves, indeed, because we do not know the language we are written in. For of all the muted mysteries spinning ceaselessly within the silent-functioning cells of twin brain-hemispheres, Science affords us but the scantest and most sketchy information. That the grey matter coating the brain-convolutions is the site of mentality; that the higher the intelligence, the deeper and more intricate these convolutions are; that disease of a certain area destroys the power of speech; while disease of some other occasions paralysis of this or that group of muscles, loss of sensation in this or that tract of skin. Baldly it states that a portion of a certain convolution controls a certain movement of a hand. But the thousand and one emotions and incentives prompting such movement, and differentiating the resulting action across the extensive range between the noblest benefaction and the blackest murder, baffle every scientific method. The processes of Mind and Impulse occur on planes we have no means of penetrating, possess no appliances whereby to estimate the ethereal undulations thereof. What are we? Who are we? Whence are we? Whither do we go? All is locked within the occulted silence of our hundred million brain-cells; each of which holds and keeps its own intrinsic secret; each the mysterious record, it may be, of one of those countless experiences, forms and phases, ancestral or individual, whereof every living person is the last resultant. But the Twin-hemispheres, face to face within the skull, like opposite pages of a book, are key to one another; one page written in the mystical language of The Past and Future, the other in the concrete language of The Present. II