Penguin’s Who Was? series tells the incredible stories of trailblazers (开拓者), legends, innovators, and creators. The following are frequently asked questions:

How many Who Was? titles are there?

About 250 Who Was? titles have been published since the series first began 20 years ago. And with the addition of the What Was? and Where Is? series, readers now have more than 300 amazing books about influential people, world-famous landmarks, and interesting historical events.

How do you choose the subjects for the Who Was? titles?

The subjects for the Who Was? series are often decided quite far in advance. People who are the first at something, or the best at what they do, or who have made major contributions in their field—and sometimes all three—make the best subjects.

What was the first Who Was? book?

The first four Who Was? books—Who Was Sacagawea?, Who Was Ben Franklin?, Who Was Albert Einstein?, and Who Was Annie Oakley2—were actually published on the same day. So when February 18 rolls around, be sure to wish these books a Happy Birthday!

Does the same person illustrate every cover?

Just about every Who Was? cover (except two)is illustrated by Nancy Harrison, who has been working on the series since the very first book.

How long does it take to complete one book?

It can take years! And sometimes the books are finished much more quickly. From the time an author is contracted to write the manuscript, through editing, copy editing, design and illustration, to publication, it takes—on average—eighteen to twenty-four months.

Dwayne Johnson said this week he returned to a 7-Eleven in Hawaii to “right the wrong” of stealing candy when he was a teenager.

In an Instagram post, the star explained that his family was “broke as hell” when he was living on the island and, for nearly a year when he was 14, he would steal a Snickers (士力架) bar from the store on the way to the gym “every day” as his pre-workout snack because he couldn’t afford to buy one.

He recalled that “the same clerk was there every day and always just turned her head and never searched me”, but admitted that his actions had been weighing on his conscience (良心) for three decades.

Johnson documented the recent visit to the store, in which he emptied the shelves of every Snickers bar, bought them and then left the candy bars for any customer to take for free.

“If somebody looks like they’re stealing Snickers, give them these so they don’t steal it,” Johnson told the store clerk.

He wrote that he realized the deed might seem “silly”, but every time he came back home to Hawaii and drove by 7-Eleven, he always knew he needed to go in and clean out every Snickers bar they had — the right way.

Johnson racked up a bill of $298 and also tipped the clerk who had to count the dozens of bars he bought and another cashier who was working at the time. The former wrestling star even posed for selfies with fans while trying to film the visit.

“We can’t change the past and some of the dumb stuff we may have done, but every once in a while we can do something to make up for that fault — and maybe put a big smile on some strangers’ faces,” Johnson said.

Be it sugar, computer games or social media, the response in our brain is the same: It produces the “feel-good” neurochemical called dopamine（多巴胺），which brings feelings of pleasure and motivation. “It may be even more important for motivation than for actual pleasure,” says Dr. Anna Lembke, a Stanford Medical School psychiatrist and researcher.

A dopamine hit brings about pleasure, which is quickly followed by pain, in order to keep us motivated. Lembke says this balancing see-saw of pleasure and pain made sense in the time of early humans, when they had to constantly search for basic needs—food, water, and shelter. “It’s really a smart method to make sure that no matter what we do, that’s pleasurable. It doesn’t last very long and it's followed by pain so that immediately we're searching again,” she explains.

But, in modern life, we live in a world of abundance, and Lembke says our brains weren't evolved for the “fire hose of dopamine” of sugar, social media, the Internet, TV, drugs or anything else so easily available. In short, Lembke says, almost every behavior has become a drug.

When we're repeatedly exposed to our pleasure-producing stimuli（刺激物），our brains adjust and, eventually, we need more and more just to feel “normal”, or not in pain. That’s called a “dopamine deficit state”, and the cycle that leads us there can actually lead to depression or anxiety.

Finally, Lembke says, this is a universal problem—not one limited to those of us struggling with the disease of addiction—that has come with living in modern life.

To maintain balance and wholeheartedness, we have to strike a pleasure-pain balance, which, in a time of abundance and over-consumption, means intentionally avoiding pleasure and seeking the kind of purposeful pain that keeps us healthy, such as exercise or resisting certain temptations. “By doing that,” Lembke says, “we will reset reward pathways and ultimately be a lot happier. It's simple but not easy, but it's well worth doing.”

The Dead Sea is an amazing wonder of the world:the lowest exposed spot on Earth,where the water is so full of salt that bathers float right to the top.

But today the Dead Sea is drying up, and its banks are collapsing. The water level is dropping close to 4 feet every year. The main part of the lake is now around 950 feet deep—about 15%shallower, and a third of the surface area, compared to its shape half a century ago.

“You’ve seen a living disaster in front of your eyes,“ says Jake Ben Zaken, an Israeli who says he operates the only passenger boats on the Dead Sea.

As the lake recedes, it changes the landscape around it in both beautiful and harmful ways. Beautiful salt formations are revealed where the water dries up. But there are also terrible scenes of beaches and parking lots swallowed up by sinkholes along the shore.

Solutions have been proposed to replenish(填满)the Dead Sea, but no significant action has been taken to prevent its further destruction. Climate change makes recovery of the lake seem even further out of reach.

The Dead Sea is a landlocked lake that’s partly in Jordan, Israel and the Israeli-occupied West Bank. The lake—named the Dead Sea because it contains too much salt and is not suitable for aquatic(水生的)life—has been drying up for decades.

”It’s a human-made problem," say environmental researchers and officials. In a region where water is rare, Israel, Jordan and Syria in the last several decades have diverted(改道)the freshwater sources that feed the Dead Sea, for drinking water and irrigation. Plus, Israeli and Jordanian companies evaporate(蒸发)Dead Sea water to harvest its rich minerals for export. The part of the lake with Israeli hotels, a popular spot for tourists to float in Dead Sea water, is actually an artificial evaporation pool in the lake’s southern basin.