World of Sudoku - Akash Doulani - Bog

This is the Ninth Book in the World Of Sudoku Series of Handcrafted Sudoku Books. The book contains 120 handcrafted Killer Sudokus with varying levels of difficulty. Killer Sudoku is probably the most common variant of sudoku. It is a variant which is enjoyed thoroughly by sudoku solvers. Most of us have come across a Killer Sudoku in various newspapers, magazines or books. In a Killer Sudoku, there are cages covering certain cells and the sum of the digits in each cage is given at the top left corner of the cage. Digits cannot repeat inside any cage. The challenge and the beauty of a Killer Sudoku is to solve the puzzle keeping the Classic Sudoku rules in mind and also getting the cage sums correct.
The sudokus are arranged in order of difficulty based on the test solve timings of Édouard Lebeau. The sudokus are test solved by Édouard Lebeau - a French solver and setter. His timings for each Sudoku are mentioned.
Each Sudoku also has an Online Solving Link. Solvers can use the links to solve the Sudokus online.
Another useful feature of the book is the exhaustive killer cage combinations given at the end of the book, which helps in finding combination of digits for the cages.