What causes diseases and illnesses? How did the doctors diagnose and observe patients when there were no thermometers and stethoscopes? What is a CT scan and who developed it? This Encyclopedia will answer these and more hows and whats for you. Learning is made simpler with well-labelled diagrams and an extensive glossary of difficult words. Bonus: The book comes loaded with Isn't It Amazing-- a section of fun facts to keep you glued for more.