The Ultimate Killer Su Doku Book 1 is a challenging collection of 200 deadly killer sudoku puzzles designed for adults. Created by the experts at The Times, this book offers a thrilling test of logic and problem-solving skills. With increasing levels of difficulty, this genre-defining puzzle book will keep even the most seasoned sudoku enthusiasts on their toes. Perfect for those seeking a mental challenge, this book promises hours of entertainment and satisfaction for those who dare to take on its formidable puzzles.