This book consists of 72 puzzles of each of two major Japanese grid-based logic puzzles, Slitherlink and Masyu. The goal of these puzzles is to place lines in a grid such that a single closed loop is formed, following the instructions and clues provided.
Slitherlink rules are much easier to understand. Loop segments are placed along the sides of squares such that the number shown in the square matches the number of loop segments along the four sides. Clue numbers range from 0 to 3, and not all squares contain a clue. In this book, all of the clues are 180-degree symmetrical (as they are with Nikoli's standard Sudoku puzzles).
Masyu rules are more complicated. Clues consist of white and black circles in some of the squares. How the loop proceeds through these squares is based on their color, with these conditions: It must proceed STRAIGHT through a WHITE circle; it must turn in the square immediately before or after that square; it must TURN (90-degrees) through a BLACK circle; it may NOT turn in the squares immediately before and after that square.
These are quality puzzles, as one would expect from Nikoli. The paper is bright white and thick stock, ready for erasing as needed, and the spiral binding allows the book to open flat. The page size is nice for easy holding. There is little white space, and the font is as large as possible (some of the harder, and hence larger, puzzles look cramped on the page). Highly recommended.