New Yorker magazine writer Rebecca Mead grew up in Weymouth, a quiet English seaside town that she could not wait to leave.

At school she was taught Middlemarch, and fell in love with a book that she has returned to regularly ever since. As she writes in this uneven but intriguing blend of memoir and literary biography, "Middlemarch inspired me when I was young and chafing to leave home; and now, in middle life, it suggests to me what else home might mean, beyond a place to grow up and grow out of."

Home for Mead now is New York, where she lives with her husband, by whom she has three stepsons, and a fourth son of her own. Even so, the book is infused with Englishness, though she assiduously avoids nostalgia. Subtitled My Life With George Eliot, The Road To Middlemarch is a thoughtful and perceptive account of Eliot's masterpiece, and the ways in which the novelist's unconventional, often unhappy life shaped its themes and its tone. Those looking for a full biography will be disappointed, although Mead is so deft she lightly covers an abundance of fact without the reader noticing. Mead's focus on Middlemarch, which surpassed all the author's works and much else in the English literary canon, is a superb device for getting to the heart of clever, priggish Marian Evans and the events and ideas that formed her. Less successfully, it is also an account of a reader's growing admiration for what the book can offer her as she matures.

That Eliot also became a stepmother, when she and her married lover George Lewes moved in together, infuses Mead with fellow feeling. George Eliot suddenly had not just a husband - as she insisted on calling him - but also three boys. Mead's appreciation of the effect family and contentment had upon the novelist sheds a convincing new light on the richness of Middlemarch.

"A book may not tell us exactly how to live our own lives, but our own lives can teach us how to read a book. Now when I read the novel in the light of Eliot's life, and in the light of my own, I see her experience of unexpected family woven deep into the fabric of the novel - not as part of the book's obvious pattern, but as part of its tensile strength."

Mead interleaves her own biography throughout this book, but while she has a likable personality, the strength of this work is the anatomy it offers of one of the greatest novels ever written. In the process, she shows the ugly duckling growing into the swan, though George Eliot's famously plain looks - Henry James called her a "horse-faced bluestocking" - did not improve with age.

Only her beloved George Lewes, from whom she took her pseudonym, seemed undaunted by her severe appearance and brilliant mind. Though Mead takes rather too long to introduce Lewes properly, her depiction of this love match is one of the joys of her book, the equally unprepossessing Lewes emerging as a man of great charm and kindness. Not only did he first suggest that she turn to fiction, but he arranged household matters so that she could concentrate on her writing.

Described by Mead as "the great artist of disappointment", Eliot stirred into Middlemarch a lifetime's experience of frustration, hurt and late-found love. Few, if any, novels surpass it for wisdom. Mead's personal response to it is perhaps more powerful than for most, but that is what makes this book more than an act of literary adoration. There's something almost spiritual about her rapport with book and author.

One cannot always identify with this intensity, and at times the connections she draws between her own commonplace circumstances and those of Eliot are stretched decidedly thin. That aside, this is a valuable and most readable homage to a complicated and often misunderstood woman and her magnum opus. Eliot's eldest stepson hotly defended her against critics, an act that speaks for itself: "If she hadn't been human with feelings and failings like other people," he said, "how could she have written her books?"