This activity book for adults was created and elaborated by an engineer, but with a great passion for sudoku. It is designed for all Sudoku lovers and enthusiasts, but due to its high level of complexity it is specifically geared for expert or very advanced players. It has 80 challenges that will test your logic, reasoning and patience like never before. We invite you to this challenge to test your problem-solving talent with these 80 puzzles designed by a Sudoku expert for only a small group of enthusiasts with a high IQ. Only 16 x 16 square grid puzzles are included in this Super Sudoku that we estimate will challenge even the most experienced Sudoku players. Each puzzle includes an area for annotations and calculations, a time table is also included so you can record the start and end of each challenge and keep track of the time taken to solve each sudoku to compare the speed and skill of solving the challenge with other players or experts. All solutions appear at the end of the book. 1. Contains 80 super puzzles designed by a Sudoku expert, with 16 x 16 grids, that will keep you busy for a few hours. 2. This Activity Book is recommended for expert players only, there are no warm-up puzzles, it goes straight to games with levels of complexity, difficult, very difficult or extreme. If you require to warm up before with 9 x 9 grids or low to intermediate difficulty levels, this activity book is definitely not for you. 3. Each page features a time-keeping chart, allowing you to track your progress and compete against yourself or your friends to see who can solve the puzzles the fastest. 4. Sudoku is proven to stimulate the brain by improving critical thinking, problem solving skills and memory retention. 5. This book provides countless hours of mental stimulation. Whether for commuting to work or just relaxing at home, it is the perfect way to keep the mind awake and entertained anytime, anywhere. 6. Solutions to all of the puzzles are included at the end of the book. 7. 192 pages. Size: 8 1/2 x 11 inches. 8. Puzzles printed in Large Format (One Sudoku game per page) for easy viewing. 9. Beautiful cover crafted with the help of Artificial Intelligence. 10. Age Range recommended: + 14 years to 100. Say goodbye to the ghost of Alzheimer's, say goodbye to boredom and hello to a satisfying mental escape from everyday anxieties. Grab your pencil and eraser, calculator (if you want), sharpen your mind and get ready to use the dendrites of each and every neuron in your brain to conquer each of the 80 challenges in this Super Sudoku.