Barry R. Clarke writes for The Daily Telegraph, Prospect magazine (UK), and Brain Games. His puzzles have also appeared in New Scientist, The Sunday Times, The Sunday Telegraph, and Readers Digest. He has academic publications in quantum mechanics, and an academic book The Quantum Puzzle (World Scientific Publishing, 2017) that sets out his theory of the mass vortex ring. In 2013, he was awarded a PhD for his thesis "Francis Bacon's contribution to three Shakespeare plays". His previous puzzle books include Mathematical Puzzles and Curiosities (Dover, 2013), and Brain Busters (Dover, 2003). His Challenging Logic Puzzles Mensa is an amazon bestseller having sold over 80,000 copies (May 2017).