The Dewy Morn by Richard Jefferies

And while her physical frame grew, and her moral being was strengthened, all these nine years from girlhood to womanhood, a colourless eye watched her -- the eye of Robert Godwin. There is something grim -- weird -- almost terrible in the thought that even this pure and beautiful creature could not exist without so opposite a nature stealthily regarding it.

Not the faintest suspicion that Robert Godwin cared for Felise, or indeed for any woman, ever occurred to anyone. The man was so absolutely concentrated, it precluded the very idea of his thinking of a second person.