Cherished Reader,

Should you come upon Enchantress of Numbers by Jennifer Chiaverini (Dutton, 426 pp., ★★★½ out of four), consider yourself quite fortunate indeed.

As with Chiaverini’s Mrs. Lincoln’s Dressmaker, Enchantress heralds a woman whose contributions are relatively overlooked in history. Ada Byron King was a pioneering mathematician whom some consider the first computer programmer. She overcame her unwanted celebrity as the daughter of English Romance poet Lord Byron — and the strictures on 19th century womanhood — to forge a career.

Ada’s heiress mother, Annabella, becomes engaged to the scandalous Byron despite warning signs as glaring as a billboard in Times Square (unusually passionate clinches with his male best friend and, perish the thought, Byron’s own sister). Alas, the marriage of the prim, practical Lady Annabella and the louche Lord Byron collapses soon after Ada’s birth.

Appalled by Byron’s cruel and manic behavior, Lady Annabella is determined to overcome the tempestuous “Byron blood” her daughter shares. She forbids any activity that would encourage Ada’s imagination, from fairy tales to her dream of learning to fly.

With little interest in the daily demands of motherhood, Annabella spends much of her time convalescing at various health spas while a series of nurses, nannies and tutors raise Ada. When Ada becomes too fond of a nanny, Annabella quickly dispatches them.

Through one cruel emotional blow from her mother after another, Ada remains determined to please her, writing daily letters about her studies and passion for mathematics while her mother travels. But to Annabella, passion sounds much like mania, another Byron quality she seeks to quash.

And oh, those letters. Enchantress is a quiet tribute to the art of letter writing, as Ada carefully crafts near-daily letters to family, friends and mentors. Ada is forced to maneuver past so-called supportive men who fear her intense interest in math and science is a sign of illness in a woman. 

Nevertheless, she persisted, and wrote a scientific paper about the potential uses of Charles Babbage’s analytical engine — an early computer — that was so admired, the U.S. Department of Defense in 1980 named a new computer language “Ada” after…