As is the custom, the third book in this science series (written in 1989) picks up where the second story left off. Ms. Frizzle is showing her students a filmstrip about the human body. "We're going to learn all about ourselves," she says. Then she announces the next field trip - the class is heading to the museum to "see an exhibit about how our bodies get energy from the food we eat." However, anyone who has even an inkling as to the kind of person Ms. Frizzle is should know that things rarely, if ever, go according to plan. A field trip is never just a field trip when you're taking a ride aboard her magic school bus.

The Friz and her students stop at a park for lunch before arriving at the museum. Afterward, everyone goes back to the bus . . . except for Arnold! He's still sitting at a picnic table, daydreaming and eating a bag of Cheesie-Weesies. And before the class realizes what is happening, the bus shrinks to the size of a Cheesie-Weesie . . . where it is promptly downed in one gulp by Arnold!

"I thought we were going to the museum," says one student.

"There's been a slight change of plans," explains Ms. Frizzle. "We're being digested instead."

Why visit an exhibit about the human body when you have a magic school bus and a teacher like Ms. Frizzle who can take you directly to the source?

If "At the Waterworks" was like priming the pump, and "Inside the Earth" was like getting the ball rolling, "Inside the Human Body" is like plowing full-steam ahead. Cole and Degen have firmly established themselves as a literacy force to be reckoned with; this is proven in the confidence of the writing and the boldness of the illustrations. There is so much going on in this story that you almost need a scorecard to keep track of it all. It seems as though Cole and Degen are bound and determined to one-up themselves with every book they come out with.

A list of some things Ms. Frizzle educates her class about would include: blood cells (red and white), blood vessels, digestion, germs, the heart, lungs, molecules, oxygen, plasma, the small intestine, etc. Do you know what villi are? You will after you read this book! Any idea what the cerebral cortex does? Ms. Frizzle will show you! Ever wondered why you sneeze? The answer resides in this story!

"Inside the Human Body" deserves just as much, if not more, a home on a person's bookshelf as does "At the Waterworks" and "Inside the Earth." Cole and Degen loaded their latest adventure to the bursting-point with information. You can see the growth author and illustrator have taken since their inaugural effort with "At the Waterworks." They prove that some things do, indeed, get better with age.

At the end of "Inside the Human Body" is a true-false test to help readers distinguish what things were true in the story and what things were made up. And, of course, Ms. Frizzle drops another clue as to where her next great adventure will take us. I'm pretty sure the class will think of their next field trip as out of this world!

It doesn't seem possible, but Cole and Degen managed to improve upon an already-winning formula. They are both in top form with "Inside the Human Body," a field trip that will take you from the brain to the small intestine and back again. Well, what are you waiting for? Hitch a ride on the magic school bus!

As Ms. Frizzle herself would say, "Seatbelts, everyone!"