This book is for advanced Sudoku/Ken-Ken lovers who are looking for a challenge. The puzzles, which utilize standard operators and the modulo function, are rated from "easy" to "nearly impossible." (My experience indicated some disagreements with the rating system, but that could just be a function of my approach to the puzzles.) The puzzle sizes range from 6x6 (for twin puzzles where two puzzles are solved simultaneously) to 10x10.
No solutions are provided in the book. For me, this was a plus, since it eliminated my tendency to peek at the answers and instead forced me to work harder at finding the solutions. Getting the solutions does require the solver to email Patrick Min; when I tried that, a reply came back very quickly with the solution.