What did Isaac Newton do when his cat had kittens? Who had green eyes, bright red hair and invented the pendulum? Who hated organ-grinders and invented the computer? The Doctor and his companions Nyssa and Tegan take you back and forth thousands of years in time to meet some of the cleverest men who have ever lived. Become a famous scientist yourself! In this exciting quiz book you'll find mind-bending puzzles and simple scientific experiments to try your hand at - and astound your friends!