In The Great Stink, Clark brings alive mid-Victorian London at a time when its sewers infested the city with the smell of human refuse in such abundance it dominated the very fabric of life there. In The Nature of Monsters Clark steps back even further in time. She takes us to the London of George I, who had come to the throne just four years before Eliza Tally arrived in the city from a small village in Northumberland on a "dishwater afternoon in January in the year of our Lord 1719."

It is a London that still remembers the Great Fire of 1666, a London that is doing its best to put behind the religious wars of the past century and, as if to prove it, the city is dominated by the dome of Christopher Wren's St. Paul's Cathedral, completed in 1710. It is also the London in which the South Sea Company induced rich and not so rich to invest in its stock. The South Sea Bubble, as it has entered history, burst after less than two years after Eliza's arrival, leaving many destitute, even committing suicide, not unlike the Stock Crash of 1929.

Clark's books, however, are not much concerned with the big names and their lifestyle that define the period to which the stories allude. Her novels are about the ordinary people of teaming London, their ambitions, hopes, fears and general social attitudes. In The Nature of Monsters she adds superstitions that define an age just awakening to scientific discoveries in the medical field. Superstitions are hard to let go off even now, but in 1719 the belief that whatever a pregnant woman experiences, or sees, is 'imprinted' on the fetus she carries, was firmly held onto despite obvious contrary evidence.

Eliza Tally was just 16 years old, and pregnant, when she embarked on her journey to London from a village outside Newcastle. She left behind a village where superstitions had a strong effect on how the villagers viewed the local midwife, her mother. Growing old, Ma Tally was slowly being seen by her neighbors more as an old crone, who affected children negatively, rather than as the helpmeet of a woman in labor. Besides, the villagers feared she might soon be a burden on the public purse because "she was like all midwives of her sex prevented by law from charging for their services and forced to rely upon presents from patrons, a precarious business since their generosity was inclined to run in inverse proportion to the fullness of their pockets." Males, who practiced midwifery, had no such pecuniary restrictions.

Ma Tally gambled on her future by encouraging her daughter to get involved with the son of a Newcastle merchant. The gamble failed and Mary, to save the honor of the young man, is sent off to London as a servant. We learn about Eliza's story through her first-person narrative which alternates with journal entries and letters written by or to her employer, the apothecary Grayson Black. His great ambition is to achieve recognition by the Royal Society for his scientific experiments, which will, he is sure, prove that it is the "nature of the maternal passions" that decide the normalcy or abnormality of a child. Eliza and another of his servant girls, Mary, are to be the proof of his theories.

Clark captures London and its inhabitants with a richness of language that denies the current tendency to forgo the lyricism of our language. Her words are so evocative that one can smell, hear and see the London of the second decade of the 1700s. And, what we thank her for, aside from this rich gift of words, is that she achieves this without resorting to the usually fatal attempt to create archaic speech, although she gives us a rich compendium of words we no longer hear today. We know that Eliza speaks with a Northern English accent and that she has trouble getting her tongue around the Southern speech and vocabulary that will eventually dominate English. But, we are spared the recreation of her speech pattern.

When the novel begins, Eliza is a rather self-centered young girl; by its end, she has matured and has turned into a caring woman. Clark achieves this without being maudlin. At the start of the book she gives us some great scenes of a girl's awakening to sexual desire that leads her astray, at its closure we meet a maternal figure, who has learned to resist temptation. As for Mary, the girl's sweet character, despite her mental and physical handicaps, rings true. Parents with handicapped children of this particular type will often state how they are blessed by the sweet nature of their afflicted children. So, not only has Clark done her historical research well, she has also breathed real life into her characters.

Grayson Black, out of necessity, remains a shadowy, somewhat two-dimensional character. But that does not detract from the highly engrossing and enjoyable read. As for his addiction to opium, Clark captures the effects of the drug on the apothecary to perfection. He too, like Eliza's mother, gambled because he understood the nature of opium, and like Ma Tally, the gamble failed to pay off.

Most of all, through all of the female characters in this book, including the apothecary's wife, Clark makes us aware that women had to resort to all sorts of tricks to survive in a world in which they were essentially powerless. Mrs. Black is not an admirable sort, but one feels just a tinge of pity for her at the end. One does that, perhaps, because Clark's book is not only about horrors—there are some stark, grisly scenes—but because its nature is essentially redemptive.

Clark also manages to surprise us with the outcome of relationships. Eliza meets a kindly Huguenot bookseller, who seems to offer her a way out of her predicament, and then there is Mr. Jewkes, whom Eliza sees as a villain. Yet, neither man is who or what he seems to be, and even Edgar Pettigrew, the apothecary's calculating assistant fits into the redemptive nature of the book.

The Nature of Monsters is, most of all, about the nature of humans. It reveals to us that monsters are not created through physical pressures or abnormalities, but that they are created through personal choice. The true monsters of history, invariably, were men and women who chose to go down a dark path devoid of mercy, while the angels were those who grasped for the light even when catastrophe seemed to engulf them.