PopCo by Scarlett Thomas (Very good, 2004, Pbk, 505 pages, Harcourt, Inc.)

Used in very good condition: cover has slight wear; inside like new. ISBN 015603137x

PopCo tells the story of Alice Butler—a subversively smart girl in our commercial-soaked world who grows from reclusive orphan to burgeoning vigilante, buttressed by mystery, codes, math, and the sense her grandparents gave her that she could change the world.

Alice—slight introvert, crossword compositor—works at PopCo, a globally successful and slightly sinister toy company. Lured by their CEO to a Thought Camp out on the moors, PopCo's creatives must invent the ultimate product for teenage girls.

Meanwhile, Alice receives bizarre, encrypted messages she suspects relate to her grandfather's decoding of a centuries-old manuscript that many—including her long-disappeared father—believe leads to buried treasure. Its key, she's sure, is engraved on the necklace she's been wearing since she was ten.

Using the skills she learned from her grandparents and teaching us aspects of cryptanalysis, Alice discovers the source of these creepy codes. Will this lead her to the mysterious treasure or another, even more carefully guarded secret?