Only diehards need apply These incredibly difficult sudoku are made to challenge even the most expert solver and strain their brains to bursting. Each puzzle requires upper-level strategies that have been honed to perfection from regular practice. Designed by powerhouse sudoku creator Frank Longo, they'll have dedicated fans tearing their hair out-and loving every moment.
"This is a bind-up of books 2, 3, and 4 our four-part" Absolutely Nasty "sudoku series."
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