As a young girl, Katya Geller learned from her mother that math was the answer to everything. Now, approaching forty, she finds this wisdom tested: she has lost the love of her life, she is in the middle of a divorce, and has just found out that her mother is dying. Half-mad with grief, Katya turns to the unfinished notes for her mother’s last textbook, hoping to find guidance in mathematical concepts.

With humor, intelligence, and unfailing honesty, Katya traces back her life’s journey: her childhood in Soviet Russia, her parents’ great love, the death of her father, her mother’s career as a renowned mathematician, and their immigration to the United States. She is, by turns, an adrift newlywed, an ESL teacher in an office occupied by witches and mediums, a restless wife, an accomplished writer, a flailing mother of two, a grieving daughter, and, all the while, a woman in love haunted by a question: how to parse the wild, unfathomable passion she feels through the cool logic of mathematics?