Book excerpt: Broaden your logic skills and identify the difficulty level right for you with a total of one hundred ninety new Sudoku-12, Sudoku-12up, HyperSudoku-12, tpsmith, Sudoku-15, Sudoku-15up, HyperSudoku-15, Sudoku-16, and HyperSudoku-16 logic puzzles, complete with step-by-step deductive solutions for every puzzle. In this series, puzzle difficulty ranges from Easy to TournamentPlus. After working a few puzzles at each of the many levels found in this book, you will know what level of difficulty you enjoy most and which level-specific book to look for next. This book is a new type of Hybrid eBook/Print book. A hybrid book consists of a traditional paperback book, containing puzzles and answers, and an on-line companion set of web pages for the print book, containing detailed step-by-step solutions for each puzzle, instructions for each puzzle type, and other information related to the paperback version of the book. Each print book title has a unique Internet web URL that points the reader directly to the eBook information for that particular print book. You can preview the on-line extras and step-by-step solutions for this particular book at its URL: http://www.grouppuzzles.com/titles/B669BEBF/ The "Variation" books are designed to help people discover the puzzle types and difficulty levels that they are most comfortable working. For this reason, they contain puzzles with multiple puzzle types, multiple puzzles levels, or both. Variation books that contain more than one puzzle type will only contain puzzles with similar group sizes so that all of the puzzle types in the book will have the same general puzzle complexity even when the book contains puzzles at many different difficulty levels. The motivation for this type of book organization is to permit everyone to explore which types of puzzles and which difficulty levels they prefer before they look for a book with a large number of puzzles.