Two on a Tower

The novel tells about the unhappily married Lady Constantine breaks all the rules of social decorum when she falls in love with Swithin St. Cleeve, an astronomer who is ten years her junior. Her husband's death leaves the lovers free to marry, but the discovery of a legacy forces them apart.

This is most complete treatment of the theme of love across the class and age divide and the fullest expression of his fascination with science and astronomy.