Crossword lovers are always on the lookout for a challenge—something rough enough and tough enough to give their mental muscles a real workout. These 75 puzzles fit the bill. With clues that range from geography and technology to popular culture and witty wordplay, it pushes solvers to search every nook and cranny of their brain. Adding to the fun, almost all the crosswords have a stimulating theme—like the sci-fi fun-filled "Roswell"; "Homophone Humor"; or "Award-Winning Roles." And the final puzzle tops off the collection with a real skill-tester. Can you complete it? We say no—but it’s up to you to prove us wrong!<br><br>There’s so much entertainment here, who could resist?