Gianni A. Sarcone and Marie-Jo Waeber are experts in brain training and are particularly involved in cognitive sciences (teaching methodology, creativity and communication).They have written numerous books on topics ranging from optical illusions to visual and critical thinking, and Gianni A. Sarcone is a leading authority on visual perception. His optical illusion project 'Mask of Love' was voted among the top 10 best optical illusions at the '2011 Best Illusion of the Year Contest'. The authors live and work in Genoa, Italy.