Two on a Tower is a tale of star-crossed love in which Hardy sets the emotional lives of his two lovers against the background of the stellar universe.

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.

In the 1895 preface Hardy wrote, "The scene of the action was suggested by two real spots in the part of the country specified, each of which has a column standing upon it.

[3] Hardy's intention, in his own words, was to "set the emotional history of two infinitesimal lives against the stupendous background of the stellar universe".