Aimee Bender is a young writer of critical acclaim. Her first book, The Girl in the Flammable Skirt (1998), was a collection of short stories told as if they were fairy tales. An Invisible Sign of My Own also begins with a fairy tale, and Bender holds the spell on the reader for the entire book.

Mona Gray is young and unique. She loves the world of mathematics. She buys herself an axe on her twentieth birthday because it feels right to her. She quits things just as she is getting good at them because she likes quitting things. Bender's cast of characters includes Mr. Jones, the math teacher who every day wears a number around his neck, and Benjamin Smith, the science teacher who has his students act out a different illness each week.

That Mona and Benjamin have a romance is a minor aspect of this book. Mona tries to figure out who leaves Mr. Jones's numbers outside of houses, while trying to teach mathematics to second graders. She is also coping with her father's illness and the fact that he might not make it to his fifty-first birthday.

This book is unique, as well, for its writing style. Nowhere in the entire book does Bender use a single quotation mark so the reader can tell who says what. This technique is very hard for a writer to get away with; post-modern writers use this device to deliberately mislead their readers along the way, but Bender presents Mona's first-person narrative as a friendly way to tell her story. Overall, this book is a gem of writing.