This superb sudoku collection is perfect for anyone looking for a challenge. Set over five levels of increasing difficulty, you'll see your skills improve as you work your way through the puzzles. With a beautifully designed cove and an elasticated strap, this is the ultimate treat for any sudoku aficionado!

• EXERCISE YOUR BRAIN: Give your mind a great workout as you pit your wits against these number-placement teasers.

• REDUCE STRESS: Feel your stress melt away as you focus on these satisfying puzzles.

• POCKET-SIZED: This handy layout is perfect for carrying on your travels or just to keep by your bedside.