The Sudoku Code: 200 Sudoku Puzzles. One Answer. Can You Find It?

Move over, Da Vinci! Here comes a code-breaking challenge based on today’s hottest puzzle craze—and every reader who solves the mystery wins a prize! But it’s not easy: First you have to complete 200 puzzles arranged in levels of difficulty from “Easy” to “Cruel.” Each of 100 numerical sudoku puzzles is paired with a “wordoku” puzzle using letters instead of numbers, and based on a key word or phrase. The combined answers to these puzzle pairs lead to a message containing a set of instructions. Unravel the instructions, and at last the solution appears. Solvers who follow this trail of clues to the end can proudly claim their prize: a button that’s inscribed, “I cracked the Sudoku Code!”
 
Notice
In the first printing of the book there is an error on page 125. The puzzle itself is correct, but the letters under the grid are incorrect. They should read "W H A T V I D E O" instead of "W H I T E D O V E."