A MIND AT PLAY is a book that provide us with a conscious description of the marvelous mind of Claude Shannon. Shannon was a mathematical genius in every sense of the word. His dedication to technology in addition to his intelligence and creativity lead him to the creation of new technological inventions such as the circuit, and the switch box among others. He considered that the best of his work was done when he was young. Unfortunately this genius lost the battle when Alzheimer took over his mind.