The English biographer Claire Tomalin’s memoir, “A Life of My Own,” is on one level a phlegmatic tour of a fruitful life. She guides us briskly through her childhood, her education at Cambridge University a year ahead of Sylvia Plath, her early marriage and four children, her years in London’s literary world as the editor of book review sections, and finally her emergence, starting in her 40s and 50s, as the esteemed biographer of Samuel Pepys, Jane Austen, Charles Dickens and others.

On another level, the book is one shock after another. Tomalin was a second child, born in 1933, and “as soon as I was aware of anything,” she writes, “I knew my father disliked me.” His name was Emile Delavenay, and his hostility toward her was inexplicable until much later. That is when she read, in his own memoir, that shortly before she was conceived he had considered killing her mother by pushing her from a high cliff.

Tomalin’s parents divorced, a scandal in the 1940s. Her mother was so distraught she threatened to put her head into a gas oven when her daughters left to visit their father in the United States.

At college she met Nicholas Tomalin, a dashing fellow who was president of the Cambridge Union, the university’s debating society, and co-editor of the student magazine Granta. She began contributing poems to the magazine. They fell in love, married young, had children, and Nicholas embarked on a successful journalism career.

He also cheated relentlessly. “Suddenly I found myself living through the most banal of stories, as the neglected wife of a faithless husband,” she writes. He would do things like drop off a beagle puppy in an attempt to make amends (“a gesture so inappropriate to the situation that I didn’t know whether to laugh or rage”).

When the author began to have discreet, reciprocal affairs of her own, her husband grew violent. In 1973, after reuniting with Tomalin following a separation, he was killed while reporting in Israel.

Few things were easy for the author. One of her children, a son named Tom, was born with spina bifida, a defect of the spinal cord. The author’s intense love for him, and his emergence as a vital part of the family, is intensely moving, and a reason by itself to come to this book.

I fear I am making this intelligent and humane book sound darker than it is.

“A Life of My Own” has a formal quality. Yet there is genuine appeal in watching this indomitable woman continue to chase the next draft of herself. After a while, the pages turn themselves. Tomalin has a biographer’s gift for carefully husbanding her resources, of consistently playing out just enough string. When she needs to, she pulls that string tight.