MICROBES
"Billions and billions of microbes are crawling, squirming, and squiggling all over your body right now! But don't worry. Nearly 95 percent of all microbes are harmless. (Some of the other 5 percent can make you sick, so remember to wash your hands often.) Without these invisible companions, life as we know it would not exist. Animals, including humans, could not digest their food. Plants would not. . . "

EYES
"Vision is the team captain of the five senses. Hearing, tasting, smelling, and feeling are important. But most humans get most of their information about the world through their eyes. The first "eyes" in nature appeared on sea animals hundreds of millions of years ago. They were just light-sensitive patches on the skin. But sensing light was so handy for survival that true vision began to. . . "

HEART
"As you read this, your heart is pumping about five quarts of blood throughout your body. The blood is traveling through more than 60,000 miles of blood vessels (arteries, veins, capillaries). That's enough to circle the equator twice, and then some! A heart works tirelessly over a lifetime. During an average life span, the heart beats three billion times without a single break. Not bad for a. . . "

GERMS
"Even when you close your bedroom door or take a shower, there's an audience. Trillions of microscopic animals, called microbes, are all over you. They're in your mouth, on your skin and even in important organs. Believe it or not, that's good news. Without the millions of kinds of microbes in the world, you couldn't live. For instance, some microbes help digest food and produce vitamins.. . . "

BLOOD
"Blood is a life-and-death issue. How does blood keep you alive? Every second of every day, blood delivers vital nutrients, oxygen, and other chemicals to all of your organs. It also carts away your body's waste. In addition, flowing blood can cool you off or warm you up, when necessary. Blood is also your best weapon against germs and other invaders. Your bloodstream creates microscopic defenders . . . "

5 SENSES
"What is your favorite memory? Is it a memory of a kitten purring on your lap as you stroked its warm, smooth, silky fur? Or do you recall zooming down a hill on a shiny new bicycle as the wind whistled in your ears? Perhaps your favorite memory is watching the lion tamer calm roaring lions in a circus tent filled with the buttery smell of popcorn. Whatever your favorite memory is, you have it because of your five senses: sight, hearing, touch, taste and smell."

BRAIN
"The human brain is large and in charge. It controls everything you do -- breathing, eating, reading this sentence. Everything. Humans have the largest brain for their body size in the animal world. Our closest relatives, chimpanzees, cannot perform tasks beyond those of an average toddler. What makes us so smart?"

MEDICINE
"Medicine is old. In the Stone Age, healing herbs and plants were used to cure illnesses. Operations were performed, too, using crude tools. Back then, medicine went hand in hand with superstition. Ancient healers mixed practical cures with magic charms and chants. And while the sick and injured sometimes got better, quite often they did not. In the fifth century b.c., the Greek doctor Hippocrates . . ."

SKIN
"Your heart, your brain, and your stomach are all organs in your body. An organ is a part of the body that does a specific job. Can you name the largest organ in your body? That right. It's the skin. . . . "

LUNGS
"They're squishy like sponges and stretchy like balloons. You use them every day - and night, too - no matter what you're doing. And, most likely, you never even think about them. They're you're lungs - those elastic bags with millions of tiny air pouches inside. All day long, those sacs in your chest fill and empty with the breath that feeds your body the oxygen it needs to stay alive. But, breathing isn't the only way these pouches help you be you."

MUSCLES
"Muscles are the parts of the body that let you stand, walk, run, bend, and reach. They make it possible fro you to smile, cross your fingers, and roll your eyes. They are even involved when your mouth waters at the thought of your favorite food."

CHILDREN'S BOOKS

• Eyewitness Visual Dictionary of the Skeleton.  By Richard Walker, Dorling Kindersley, 1995.
• The Skeletal System (Invisible World).  By Eduard Arnau, Chelsea House, 1995.
• Encyclopedia of the Human Body.  By Richard Walker, Dorling Kindersley, 2002.
• Human Body (Eyewitness Books).  By Steven Parker, Dorling Kindersley, 2004. 

ADULT BOOKS

• The Human Body (Scienceworks for Kids).  By Elissa Dosik Weinroth, et. al., Evan-Moor Educational Publishers, 2002.
• Head to Toe Science: Over 40 Eye-Popping, Spine-Tingling, Heart-Pounding Activities That Teach Kids About the Human Body.  By Jim Wiese, Wiley,  2000.