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.

The human brain is the most complex and poorly understood biological structure known to man. Our human brain is relatively large for our body size and wrinkled in comparison to other animals' brains. Across species, brain size and wrinkle number is related to intelligence.

University of Copenhagen researchers have made an incredible discovery seeking to learn more about the mammalian（哺乳动物的）brain. A vital enzyme（酶）, a special material, allows brain signals to be transmitted or transported. The enzyme is randomly turning on and off, even taking hours-long "breaks from work." These discoverie8 could have a significant impact on our understanding of the brain and the development of medicines. The discovery is featured on the cover of Nature.

Millions of neurons (神经元) are constantly communicating with one another, shaping thoughts and memories and allowing us to move our bodies at will. Neurotransmitters are transported from one neuron to another by a unique enzyme when two neurons meet to exchange a message.

This process is necessary for neuronal communication as well as the survival of all complex organisms (extremely small living things). Until now, researchers all over the world assumed that these enzymes were constantly active, transmitting vital signals. However, this is not the case.

It is almost impossible to understand that the extremely critical process of loading neurotransmitters in containers is carried out by only one cell per container. Especially when we find that 40% of the time these cells are switched off.

Using a new method, researchers from the Department of Chemistry at the University of Copenhagen closely examined the enzyme and discovered that its activity switches on and off at random periods of time, contradicting our previous understanding.

"Contrary to popular belief, and unlike many other proteins, these enzymes could stop working for minutes to hours. Still, the brains of humans and other mammals are miraculously able to function," says Professor Dimitrios Stamou, who led the study from the research center at the University of Copenhagen's Department of Chemistry.

    For decades, the message to students in the United States has been nearly the same: You need to go to college. Students have heard this message loud and clear, ever since their childhood. However, while encouraging students to further their education after high school is a noble and well-intentioned action, the current system in the United States has created some damaging side effects. 

    The largest and most well-known consequence is the student debt. Tuition and fees at four-year universities have risen by around 54% since 1999. Total student debt in the U. S. is estimated at around $1. 6 trillion, so much that even the world's richest man Jeff Bezos would have to increase his wealth by nearly nine times to pay off all of it. 

    Although the price of acquiring a bachelor's degree has gone up, the relative value of having the actual degree has been watered down by the fact that holding a degree is now an expectation, not a bonus. The poor return on investment is also evidenced by the massive waves of students earning degrees in fields where there simply are not enough jobs for the number of graduates, leaving young adults in debt and out of work. 

    The push for students to go to college has also prevented them from considering careers in important fields that don't necessarily require a four-year degree, such as construction and manufacturing. Despite the good pay and benefits in these industries, the lack of new blood has led to growing shortages of both workers and skills, causing delays and higher costs in projects like road repairs and infrastructure(基础设施) improvements. 

    Colleges and universities remain critical to our nation. But as a society, it would benefit us greatly to acknowledge that college isn't the only form of higher education and career preparation. Students and young adults have more options than they think and informing them of those opportunities can go a long way toward making higher education as a whole more effective, efficient and affordable.