What Mary Somerville was and what she accomplished are captured in the self-portrait that serves as the frontispiece for this book. One of the most striking characteristics of the self-portrait is the directness with which the subject meets the gaze of the viewer. She deliberately presented herself as an author, pen in hand and seemingly in the midst of composition. Her clothing seems decidedly, perhaps even selfconsciously, feminine. The face is portrayed with much more accuracy and detail than any other part of the portrait except for her hands. In fact, much of the background is treated in an impressionistic way that almost suggests that the portrait is not yet finished. For the style of portraiture of the time, the gaze is uncommonly direct. It is neither reluctant nor aggressive, but, rather, discerning, perspicacious, shrewd.

In one respect, the directness of the gaze reflects her voice as an author, the hard-won confidence and authority that Somerville enjoyed as a scientist and an intellectual. Her life story demonstrates what a great distance had to be traversed in order for her – or for any woman of her time – to overcome the norms of deference that she surmounted in meeting the viewer's gaze so directly.