David Macaulay, a bestselling author and illustrator, spoke about the process of writing his newly-released book, “The Way We Work,” which portrays human anatomy through vivid drawings of the inside of the body, at a speech at the Brattle Theater on Friday evening.

Macaulay said that his own lack of appreciation for his healthy body prompted him to learn more about physiology.

“This is one of the most extraordinary things we will encounter,” he said.

Macaulay said he hopes that readers would come away from his book with a heightened sense of appreciation for the complexities of their bodies. It took Macaulay six years to write the book, during which he took an anatomy class, watched several surgeries, and even participated in cadaver dissections.

At the talk, Macaulay showed three interpretations of the digestive system, depicting it alternatively as a factory, a river, and a college campus.

Other images included a series on the muscle-by-muscle construction of an eye that showed tiny people using a crane to lift the eyeball into the skull. Another depicted a roller-coaster, aptly titled “Ride of a Lifetime,” winding its way from a forest—the lungs—through a pumping heart.

Macaulay described the arduous process of learning about the body, which involved long hours spent sketching.

“If I can’t draw it, I can’t understand it.” He added, wryly: “I can’t wait to tackle the economic system.”

But when asked what the future holds, Macaulay said, “After doing this for six years, I don’t want to do another monster book. So I’m going to do the Earth.”

Macaulay has been widely honored for his previous work, having won a Caldecott Medal and a Boston Globe-Horn Book Award. In 2006, he was awarded the MacArthur Foundation’s prestigious “Genius Grant.”

His appearance at the Brattle was hosted by Harvard Book Store.