Ernest Hemingway was an artist of unique, transcendent gifts. He was also plagued with a debilitating mental illness. So where does Hemingway begin and the madness end? Jeff Levine examines this question.

On any given summer afternoon in Cooperstown, NY, you’re likely to hear the sweet crack of a baseball bat sending a ball sailing into the outfield, or maybe screaming past third base, as if in pain. Those sounds would be coming from Doubleday Field, a perfect little baseball diamond, enclosed by bleachers and red brick — a closely cropped meadow of dreams where people come, like members of a religious pilgrimage, to watch and honor a strange game involving four bases, 18 players and an assortment of peculiar gear and equipment, the most central being a perfectly round orb, bound over with animal hide stitched together with 216 hand-sewn loops of bright red cotton thread.

Anthropologists are explorers too, of the deep past and the human story. There have been a string of discoveries about our past that have rocked the world of evolution, and completely rearranged our view of who we are and how we got here.

Water is odd because its molecules have an abiding affection for one another. They bind in a V-shape as easily as three good friends. At the bottom of the V, the oxygen end is slightly negatively charged. At the other end, the hydrogen molecules are positively charged, also just slightly. This is why water is fluid, flowable, because its negative and positive charges easily attract its sister molecules as if in a great dance, changing partners billions of times in a blink.

Following the release of my fifth literary science book, Immortality, Inc. — Renegade Science, Silicon Valley Billions and the Quest to Live Forever for National Geographic, The Week magazine asked me to suggest six of my all-time favorite science books. I could have come up with dozens, but these six are timeless, and the ones I feel have had a profound effect on me.

The human hand is one of the most remarkable inventions in nature. Here’s the story that explains why.

LOOK at your hand. Hold it up. Flex it. Bend it. Make it act like a puppet. It’s a remarkable piece of engineering. Never before have five digits, 14 joints and 27 bones come together in such an interesting and practical way. If you turn it, eight cube-like bones connected by a matrix of tendons in your wrist and forearm enable you to rotate your hand 180 degrees. As a result, it can do things that animals in the natural world, even if they had the inclination, could never possibly carry off -- swing a baseball bat, for instance, pour a glass of milk, play a Duke Ellington piano solo, paint a portrait.