Let's review some of the year's best books so far.

The Astronaut's Guide to Leaving the Planet

In this book, retired astronaut and pilot Terry Virts paints a lively picture of life aboard the International Space Station. And he describes what it takes to conduct a successful mission. Young space enthusiasts will enjoy this guide. Ambitious astronauts will treasure it. 

Lasagna Means I Love You

In this touching realistic novel by Kate O'Shaughnessy, Mo and her grandma, Nan, live together. But after Nan dies, Mo's uncle can no longer take care of her. To deal with these changes, she starts cooking, using family recipes that she collects from friends and through her food blog. There's only one problem: She doesn't have family recipes of her own. Hoping to define what really makes a family, Mo learns there's no perfect recipe.

The Enchanted Life of Valentina Mejia

In this fast-paced adventure by Alexandra Alessandri, 12-year-old Valentina and her brother Julian are searching for mysterious creatures. Falling into another world during an earthquake, they discover a different, magical Colombia. Valentina learns that all of the legends about her country are true. But will they be able to leave this place and return home?

Just Jerry

It's written by Jerry Pinkney, who writes about his growing up in Philadelphia, Pennsylvania, during the 1940s and 1950s. He struggled with dyslexia (阅读障碍), but he always pursued his artistic calling. When he got a job at a newsstand, his boss gave him a chance to draw and sell his work. He was able to go to college to study art, and eventually built a career in publishing.

If you want to tell the history of the whole world, a history that does not privilege one part of humanity, you cannot do it through texts alone, because only some of the world has ever had texts, while most of the world, for most of the time, has not. Writing is one of humanity's later achievements, and until fairly recently even many literate (有文字的) societies recorded their concerns not only in writing but in things.

Ideally a history would bring together texts and objects, and some chapters of this book are able to do just that, but in many cases we simply can't. The clearest example of this between literate and non-literate history is perhaps the first conflict, at Botany Bay, between Captain Cook's voyage and the Australian Aboriginals. From the English side, we have scientific reports and the captain's record of that terrible day. From the Australian side, we have only a wooden shield (盾) dropped by a man in flight after his first experience of gunshot. If we want to reconstruct what was actually going on that day, the shield must be questioned and interpreted as deeply and strictly as the written reports.

In addition to the problem of miscomprehension from both sides, there are victories accidentally or deliberately twisted, especially when only the victors know how to write. Those who are on the losing side often have only their things to tell their stories. The Caribbean Taino, the Australian Aboriginals, the African people of Benin and the Incas, all of whom appear in this book, can speak to us now of their past achievements most powerfully through the objects they made: a history told through things gives them back a voice. When we consider contact (联系) between literate and non-literate societies such as these, all our first-hand accounts are necessarily twisted, only one half of a dialogue. If we are to find the other half of that conversation, we have to read not just the texts, but the objects.

Every summer, the calls of thousands of swamp sparrows can be heard across North America's wetlands. These little brown birds know only a few songs, but they know them very well. In fact, their musical set list probably hasn't changed much for centuries.

Like humans, baby swamp sparrows learn to communicate by copying adults. From a young age, they learn to copy, or mimic, songs sung by their elders. "Swamp sparrows very rarely make mistakes when they learn their songs," says biologist Robert Lachlan. In fact, their mimicry is so accurate that the music changes little between generations.

Just like children, the sparrows don't remember every song they hear. Lachlan says. "They don't just learn songs at random; they pick up commoner songs rather than rarer songs." In other words, they learn songs they hear most often. It's an example of a strategy that scientists call conformist bias. Until recently, this learning ability was thought to be special only to humans.

Between 2008 and 2009, Lachlan's research team recorded the calls of 615 male swamp sparrows across the northeastern United States. The researchers used computer software to break each song into a collection of notes, or syllables. They then measured the differences between the tunes.

The research revealed that only 2 percent of male sparrows sang a different song from the standard tune. The combination of accurate mimicry and conformist bias allows the birds to create traditions that last for centuries. "With those two ingredients together, you end up with traditions that are really stable," says Lachlan. "The song-types that you hear in the marshes（湿地）of North America today may well have been there 1,000 years ago." Lachlan's study is also among the first to measure the longevity of song traditions within a bird species.

The findings are really exciting, says scientist Andrew Farnsworth. He hopes that future research will evolve from these studies. For example, scientists may be able to identify how other animals are able to preserve their cultural traditions. "Seeing the potential for it in other organisms is super cool," says Farnsworth.