In Code: An Invitation to Tumbers, Nryptography, and Mthinking Cathematically

Sarah Flannery's In Code: A Mathematical Journey is an inspiring account of her explorations in cryptography. In particular, the book inspires in both mathematical and in human ways: the reader is left with a rich portrait of what it means to think mathematically. World-wide publicity called attention to 16 year-old Sarah's winning of Ireland's prestigious Young Scientist Award in 1999, following a year in which she won awards at local and international science fairs for her work on a new cryptography system. The use of this book in mathematics classes can motivate students and can help integrate history, biography, current events, and reading and writing with arithmetic.

The book is written almost entirely by Sarah, with a little help from her father, a mathematics lecturer at Ireland's Cork Institute of Technology. Its conversational style makes it easy to read, and the substantial mathematical passages are equally lucid. This book weaves together a personal story and a lot of good mathematics that could enrich most any high school course. One of the most inspiring aspects of the book is its reflection of Sarah's humility and down-to-earth attitude. Although she is clearly a very capable girl, Sarah rejects the genius label many in the media tried to affix to her. She lives a well-rounded life. In fact, one gets the sense that most anyone with similar opportunities to discuss mathematics inside and outside of school, a disciplined life, a substantial work ethic, and a natural curiousity for things mathematical could make similar contributions to mathematics. This in no way detracts from what Sarah has accomplished; rather, it raises some serious questions about why accomplishments like hers are not more common. Not least important is the question of how more school mathematics classes can be made into places that inspire and support the kind of learning Sarah describes.

Leaving that issue as a homework assignment, we turn now to some of the mathematics that lies at the heart of the book and at the heart of contemporary cryptography. Perhaps the following questions will inspire you and your students to read In Code, and perhaps it will in turn inspire study of cryptography or some other contemporary branch of mathematics.