Dr. Gareth Moore is the author of over 75 books of puzzles for both children and adults, and the creator of the daily brain-training site, BrainedUp.com. He creates all types of puzzles, ranging from crosswords and other word puzzles through to sudoku and logic puzzles, and all the way on to complex dot-to-dot, colour-by-number and maze books. He also creates sticker books and other types of activity content, as well as optical illusions, quizzes and trivia books. He has written several books of brain and memory training puzzles, exercises and tips, and frequently appears on TV and radio as both a brain-training and a puzzle expert.

Sidney Paget (1860-1908) was a popular British illustrator, best known for his illustrations that accompanied Arthur Conan Doyle's Sherlock Holmes stories in The Strand magazine.

George Hutchinson (1852-1942) was a British illustrator. Born in Canada, he then moved to London at 14 and studied painting at the Royal Academy. His illustrated numerous works by classic authors, including Arthur Conan Doyle, Rudyard Kipling and Robert Louis Stevenson.