Dr. Ecco: Mathematical Detective (Codes, Puzzles, and Conspiracy)

In this collection of original puzzles, games, and codes, the heroic Dr. Ecco, a mathematical detective and puzzle solver, takes on his archenemy, Baskerhound, and uncovers a plot that threatens the world. No sophisticated mathematical background is necessary to solve these challenges, which were inspired by the methods and thinking of researchers in computer science and mathematics. All you need is imagination and a passion for puzzles.
A graduate of Yale, author Dennis Shasha received his Ph.D. from Harvard and is Associate Professor of Computer Science at the Courant Institute of Mathematical Sciences at New York University. He includes complete solutions at the end of the book, and has rated the puzzles according to difficulty.