Language defines us as a species, placing humans head and shoulders above even the most proficient animal communicators. But it also beguiles us with its endless mysteries, allowing us to ponder why different languages emerged, why there isn't simply a single language, how languages change over time and whether that's good or bad, and how languages die out and become extinct.

Ever since we produced our course Thinking About Capitalism, customers have expressed interest in a follow-up course that could help them understand socialism in the same way. After much consideration, we determined that it actually would be more beneficial to create a course that compares and contrasts the two major global economic theories, examining them in ways that move past the polemics many of us are used to and looking at these systems as they relate to one another and the world at large.

There are many stories we can tell about the past, and we are not, perhaps, as free as we might imagine in our choice of which stories to tell or where those stories end. John Arnold's addition to Oxford's popular Very Short Introductions series is a stimulating essay about how people study and understand history.

Brian and Deborah Charlesworth provide a clear and concise summary of the process of evolution by natural selection, and how natural selection gives rise to adaptations and eventually, over many generations, to new species. They introduce the central concepts of the field of evolutionary biology, as they have developed since Darwin and Wallace on the subject, over 140 years ago, and discuss some of the remaining questions regarding processes.

Charles Darwin's theory of organic evolution-the idea that life on earth is the product of purely natural causes, not the hand of God-set off shock waves that continue to reverberate through Western society, and especially the United States. What makes evolution such a profoundly provocative concept, so convincing to most scientists, yet so socially and politically divisive? These 12 eye-opening lectures are an examination of the varied elements that so often make this science the object of strong sentiments and heated debate.