Excerpt from How to Create the Perfect Wife by Wendy Moore, plus links to reviews, author biography & more

Yet for all his slovenly appearance and boorish manners, there was evidently something about the youth that appealed to some men—Edgeworth for one—and occasionally some women. Day's commitment to enhancing human rights had struck a chord with fellow radicals, while his determination to help those worse off than himself had earned him many admirers. University friends at Oxford and fellow law students in London treated Day as something of an absentminded philosopher or a romantic rebel. He seemed not quite of his time. His espousal of chivalric virtues and classical heroes harked back to a past age; his opposition to class-ridden systems and traditional hierarchies seemed to anticipate a distant future. Certainly his ideas were out of pace with the consumer-driven, celebrity-obsessed, fashion-mad culture that was predominant in Georgian Britain.

At first, therefore, Day and Margaret appeared to have nothing in common. Repulsed by her brother's loutish friend and his daring ideas, Margaret kept out of his way as much as politeness allowed. Equally contemptuous of his friend's elegant sister and her polished manners, Day gave Margaret a wide berth. To Day, Margaret represented "a sort of being for which he had a feeling of something like horror," according to her brother Richard. And so for the first few weeks in the large country house the pair had maintained "an awful distance." But as they had spent more and more time together during uncomfortable meals and awkward social occasions over the early summer of 1768, they had gradually discovered some mutual interests.

Margaret found herself intrigued by the eccentric Englishman. She too had been disappointed in love— by a dashing but unsuitable English army officer— and Day offered a refreshing contrast to the fawning beaux who usually competed for her attentions. Managing to overlook his lack of grooming and poor social skills, she was moved by the powerful monologues Day delivered on improving the lot of humanity and had to admire his philanthropic plans. Drawing Day into conversation, Margaret's "easy manners, and agreeable conversation" had managed to "unbend" Day's aloof conduct, said Edgeworth.

At the same time, Day became entranced by his clever and attractive hostess. He discovered a shared interest in literature and nature as well as finding a few differences of opinion over the importance of etiquette and "aristocratic habits." According to Edgeworth, watching wryly from the sidelines, his smart little sister could always run rings around Day when arguing her point; it was only when he was alone with Day that Edgeworth found "Mr. Day's eloquence prevailed." As in the best of romantic comedies, the cut and thrust of verbal sparring led to heated passions.

At the beginning of August, Day cautiously proposed to Margaret and she tentatively accepted. When the pair announced their intentions to the assembled family, Margaret's brother had been as surprised as her father was horrified. Edgeworth senior refused point-blank to give the marriage plan his blessing, having taken resolutely against the scruffy English youth "from Prejudices too ridiculous to mention," in Day's words. But Margaret determined that she would go ahead regardless, and so the pair agreed that they would marry as soon as Day reached twenty-one the following summer. Postponing his return to London so that he and his future spouse could get to know each other a little better, Day stayed on in the Edgeworth country home as the summer faded. In retrospect this had not been such a good idea. For as Day outlined his vision of marital bliss, Margaret's ardor began visibly to cool.

Excerpted with permission from How to Create the Perfect Wife: Britain's Most Ineligible Bachelor and His Enlightened Quest to Train the Ideal Mate, by Wendy Moore. Available from Basic Books, a member of The Perseus Books Group. Copyright © 2013.