Today British poet Elizabeth Barrett Browning is remembered mostly for her love poetry — her line, "How do I love thee? Let me count the ways," written for her lover and eventual husband Robert Browning, has achieved a kind of epigrammatic immortality. In her new biography of the 19th-century English poet, the first in 30 years, British poet and author Fiona Sampson ("In Search of Mary Shelley") aims for a deeper dive into Browning's eventful life, and delivers an account of breadth and depth.

Sampson reintroduces her poetry to the 21st century, puts the more notorious aspects of the poet's life in perspective, and makes the case that Browning was not just the most notable woman poet of her day, but one of the great poets of the 19th century.

Daughter of an eccentric English landowner, Elizabeth showed literary genius early, and her chronic illnesses freed her from the obligations of a woman of her class and era. As a teenager she wrote and published essays and poetry, and as a young woman she appeared in England's foremost journals, thanks to her talent and to support by mentors, both women and men. Despite debilitating bouts of illness, she continued to write, even when confined to her bed.

Then, in her late 30s, she was contacted by poet Robert Browning, an ardent admirer of her work. "I do, as I say, love these Books with all my heart — and I love you too," he wrote in his first letter to her. They corresponded and eventually met, and in 1846 ran away to Italy to get married, a decision that enraged her controlling father, who wrote her that he considered her dead and cut her off financially (fortunately she had her own inheritance).

This well publicized series of events, and Elizabeth's eloquent love poetry ("Sonnets From the Portuguese"), turned the two lovers into the "it" couple of the 19th-century literary universe. They settled in Italy and had a son, and Browning would write her nine-book masterwork, the epic poem "Aurora Leigh," there.

Sampson provides updated research and commentary on how the Barretts' family wealth was generated largely by slaves (on family-owned sugar cane plantations in Jamaica), and shows how Elizabeth's guilt at her heritage, which enabled her to pursue an independent life as a writer, turned her toward political radicalism.

Sampson is adept at switching between personal history and literary analysis. Her account falters only with her frequent use of mirrors and reflections as a framing device for the poet's life and work, a literary conceit that detracts from the strength of the material.

In the latter part of the book, Elizabeth suffers a number of miscarriages, pursues spiritualism and becomes more dependent on opium to alleviate pain. Illness strains the couple's relationship, and the family traveled incessantly until she died in 1861.

Hers was a "life of struggle" with a bodily "machine" that often let her down, Sampson writes, but her limitations enabled her genius. Sampson does her achievement justice in this acute and well grounded psychological portrait.

Mary Ann Gwinn is a book critic in Seattle.

Two-Way Mirror
By: Fiona Sampson.
Publisher: W.W. Norton, 320 pages, $27.95.