As we grow old, we realize that we have so little time to read and there are so many great books that we’ve yet to get around to. Yet re-readers are everywhere around us. For certain fans, re-reading The Lord of the Rings is a conventional practice annually. One friend told me that Jane Austen's Emma can still surprise him, despite his having read it over 50 times.

New sudden clear understandings can be gained from the process of re-reading. Journalist Rebecca Mead, a long-time English woman in New York, first came across George Eliot’s Middlemarch at 17. Since then, she has read it again every five years. With each re-reading, it has opened up further; in each chapter of her life, it has resonated differently. Mead evidenced the large number of ways in which really good books not only stand the test of repeat reads, but also offer fresh gifts each time we crack their spines. These kinds of books grow with us.

Scientists have also recognized the mental health benefits of re-reading. Research conducted with readers in the US found that on our first reading, we are concerned with the “what” and the “why”. Second time round, we’re able to better appreciate the emotions that the plot continues to express. As researcher Cristel Russell of the American University explained. returning to a book “brings new or renewed appreciation of both the great book and its readers.”

It’s true that we often find former selves on the pages of old books (if we’re fond of making notes on the pages). These texts can carry us back to a time and place, and remind us of the kind of person that we were then. We're changed not only by lived experience but also by read experience — by the books that we've discovered since last reading the one in our hand.

More so than the movie director or the musician, the writer calls upon our imaginations, using words to lead us to picture this declaration of love or that unfaithfulness in life. A book is a joim project between writers and readers, and we must pour so much of ourselves into reading that our own life story can become connected with the story in the book.

Perhaps what’s really strange is that we don’t re-read more often. After all, we watch our favourite films again and we wouldn’t think of listening to an album only once. We treasure messy old paintings as objects, yet of all art forms, literature alone is a largely one-time delight. A book, of course, takes up more time, but as Mead confirms, the rewards make it adequately worthwhile.

We all know reading can teach you facts, and knowing the right thing at the right time helps you be more successful. But is that the whole reason just about every smart, great person you can think of, from Bill Gates to Yu Minhong, credits much of their success to their reading? Of course not.

In fact, beyond simply educating us, books have more benefits (好处). They provide inspiration, guide our decisions, and sometimes even change our lives. Reading a good book can be so amazing that you forget about your troubles for a while. On top of that, reading helps us understand people from different walks of life. It gives us a window into their minds and hearts. Reading has many positive effects on your body as well. Research shows that people who read are less likely to suffer from anxiety. Regular readers also have lower rates of heart disease than those who do not read at all or only watch television. It works better and faster than other methods of relaxation, such as listening to music or drinking hot tea.

Of course, you are reading right now, but sorry, it doesn’t count. The most important benefits come from devoting the time and attention to longer, deeper content. What type of reading is best for the brain? They believe that reading a novel closely to study literature and thinking about its value is an effective exercise in the brain, more effective than just reading for pleasure. Don’t go fooling yourself into considering a look through Facebook as a brain workout.

I use Goodreads to track how many books I read, and try to increase the number every year. If you are inspired to get through more novels this year too, keep an eye on your brain’s performance too, to see if it’s making a difference. I can safely say that you’ll be amazed at the result!

But seriously, have you read any good books lately? Let me know in the comments.

Around 50,000 years ago, Homo sapiens (智人) left Africa and travelled across the world; around the same time, all the other species began to disappear. Why the other humans died out may be the biggest confusion of the early Palaeolithic age. The common explanation is that H. sapiens was brainier than other species. These humans had better communication skills and fighting ability.

According to Jonathan Kennedy, the author of Pathogenesis, there is a better explanation for why H. sapiens won out: their immune systems were superior. As their populations expanded, genetic (基因的) diversity increased and, since they lived in Africa, much closer to the equator (赤道) than other humans, H. sapiens would have been exposed to a greater range of animals carrying a variety of virus.

As H. sapiens moved across the world, they would have been protected against the diseases carried by the other humans they met. The converse was not true, however, meaning other humans were less resistant to the diseases carried by H. sapiens.

From there, Mr Kennedy goes on to rewrite much of the history of life, with virus at the forefront. Human civilisations have been shaped by diseases and infections. Some of his most striking stories come from the Spanish defeat of the Americas. The popular story here is that the Europeans had better technology and weapons with which to beat the less advanced societies in the Americas. That’s not entirely true, Mr Kennedy says. The introduction of infectious diseases from Europe, he writes, resulted in a 90% fall in the population in the Americas.

There is a clue of pattern about this book: as soon as a new set of characters is introduced, you know infection appears. But that is just a minor criticism in a convincing account of the role of viruses in world history. It helps that Mr Kennedy’s epidemiological writing is dotted with pop-culture references: The Lord of the Rings, 2001: A Space Odyssey and so on. Despite the big ideas, therefore, his book is an entertaining read.