After a three year wait there finally is a 4th volume of the "Calcudoku, Advanced Puzzles'" series. If you're looking for the most challenging Calcudoku puzzles, then look no further. Included are: puzzles using zero, negative numbers,modulo and exponentiation operators, puzzles without operators (called ``no-op'' or ``mystery'' Calcudoku),twin puzzles, and many extra large puzzles (10x10 to 15x15), and even one 17x17 puzzle!New in this volume: more puzzle variations andmore puzzles with binary operators (including the new AND operator). This voume IV has 121 completely new puzzles, explanations for the various puzzle variations, solving strategies, and all solutions. Note: the puzzles in this book are difficult. If you're looking for "light" recreational puzzles, then avoid this book. You can submit puzzle solutions online at www.calcudoku.org and score points for each correct solution.

If you're looking for really challenging Calcudoku (also known as Kenken) puzzles, then look no further. From the reviews of the previous edition of this volume: " His easy puzzles equate to the NY Times hard -- his hard can be off the charts but all the more satisfying when solved. ", "I highly recommend this book for the avid solver." - JHackley. "These puzzles will keep you busy for hours. " - Rockman. "I have tried every difficult, advanced kenken and calcudoku book there is and this one is the most challenging." - Jorge Lobo. "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." - Richard Klein This 4th edition has 20 new puzzles (with exponentiation, without operators, with exponentiation and zero, and with negative numbers), so it now also has 121 puzzles (just like volumes II and III of the series). It also features extended explanations of the variations on the standard puzzle, as well as step-by-step solving guides for two tricky sample puzzles. Note that there are no solutions in the back (except for the example puzzles). If you do need a hint, the solution to a specific puzzle, or even all solutions, you can send me e-mail (address is in the book) and I'll send them as a PDF.

Due to popular demand there is now a 3rd volume of the "Calcudoku, Advanced Puzzles'" series. If you're looking for the most challenging Calcudoku puzzles, then look no further (even a few easy ones have been thrown in :-). Included are: puzzles using zero, negative numbers,modulo and exponentiation operators, puzzles without operators (called ``no-op'' or ``mystery'' Calcudoku),twin puzzles, and many extra large puzzles (10x10 to 15x15), and even one 17x17 puzzle! This voume III has 121 completely new puzzles, explanations for the various puzzle variations, solving strategies, and all solutions. You can submit puzzle solutions online at www.calcudoku.org and score points for each correct solution.

Looking for a different kind of Sudoku challenge? Then try this third volume of 3D Sudoku! These 101 Jumbo 3D Sudoku puzzles solve just like regular Sudoku puzzles, but now each 3x3 box is written on the face of a cube and the rows run in all different directions, bending back and forth with the contours of the stacked cubes. Perfect for Sudoku solvers of all skills, the puzzles are arranged in increasing order of difficulty throughout the book, but all of the puzzles are designed to be solved by simple logical deduction - absolutely no guessing is ever required!

Let the number crunching begin as you embark on a journey to become one of the KenKen Elite! If you can complete these infernally difficult puzzles, then you will have achieved the highest honor bestowed upon any KenKen-er. So sharpen that pencil and get ready for 100 of the most grueling, mind-numbing KenKen puzzles ever...difficulty level=expert^2.

This book shares the latest developments and advances in materials and processes involved in the energy generation, transmission, distribution and storage. Chapters are written by researchers in the energy and materials field. Topics include, but are not limited to, energy from biomass, bio-gas and bio-fuels; solar, wind, geothermal, hydro power, wave energy; energy-transmission, distribution and storage; energy-efficient lighting buildings; energy sustainability; hydrogen and fuel cells; energy policy for new and renewable energy technologies and education for sustainable energy development.