Yet it is rare to find someone prepared to defend all freedom of speech, especially if the views expressed are obnoxious or obviously false. So where do we draw the line? How important is our right to freedom of speech? In this accessible and up-to-date Very Short Introduction, Nigel Warburton covers a wide range of controversial free-speech issues, from Holocaust denial and pornography to the status of modern copyright law. The book offers a concise guide to many of the vexing issues concerning our right to speak freely, including: Should a civilized society set limits on freedom of speech? How can we balance free speech with the sensitivities of religious and minority groups? How have digital technology and the Internet changed the debate?

    In the 1990s he and his colleagues made headlines with the discovery that the last ice age came to an abrupt end over a period of only three years. Here Alley offers the first popular account of the wildly fluctuating climate that characterized most of prehistory--long deep freezes alternating briefly with mild conditions--and explains that we humans have experienced an unusually temperate climate. But, he warns, our comfortable environment could come to an end in a matter of years."The Two-Mile Time Machine" begins with the story behind the extensive research in Greenland in the early 1990s, when scientists were beginning to discover ancient ice as an archive of critical information about the climate. Drilling down two miles into the ice, they found atmospheric chemicals and dust that enabled them to construct a record of such phenomena as wind patterns and precipitation over the past 110,000 years. The record suggests that "switches" as well as "dials" control the earth's climate, affecting, for example, hot ocean currents that today enable roses to grow in Europe farther north than polar bears grow in Canada. Throughout most of history, these currents switched on and off repeatedly (due partly to collapsing ice sheets), throwing much of the world from hot to icy and back again in as little as a few years.Alley explains the discovery process in terms the general reader can understand, while laying out the issues that require further study: What are the mechanisms that turn these dials and flip these switches? Is the earth due for another drastic change, one that will reconfigure coastlines or send certain regions into severe drought? Will global warming combine with natural variations in Earth's orbit to flip the North Atlantic switch again? Predicting the long-term climate is one of the greatest challenges facing scientists in the twenty-first century, and Alley tells us what we need to know in order to understand and perhaps overcome climate changes in the future.

    Scientists around the world are currently monitoring the sixth extinction, predicted to be the most devastating extinction event since the asteroid impact that wiped out the dinosaurs. This time around, the cataclysm is us. In prose that is at once frank, entertaining, and deeply informed, The New Yorker writer Elizabeth Kolbert tells us why and how human beings have altered life on the planet in a way no species has before. Interweaving research in half a dozen disciplines, descriptions of the fascinating species that have already been lost, and the history of extinction as a concept, Kolbert provides a moving and comprehensive account of the disappearances occurring before our very eyes. She shows that the sixth extinction is likely to be mankind's most lasting legacy, compelling us to rethink the fundamental question of what it means to be human.

     It was an ancient puzzle that stymied history's greatest minds: How did the fossils of seashells find their way far inland, sometimes high up into the mountains? Fossils only made sense in a world old enough to form them, and in the seventeenth century, few people could imagine such a thing. Texts no less authoritative than the Old Testament laid out very clearly the timescale of Earth's past; in fact one Anglican archbishop went so far as to calculate the exact date of Creation...October 23, 4004, B.C. A revolution was in the making, however, and it was started by the brilliant and enigmatic Nicholas Steno, the man whom Stephen Jay Gould called "the founder of geology." Steno explored beyond the pages of the Bible, looking directly at the clues left in the layers of the Earth. With his groundbreaking answer to the fossil question, Steno would not only confound the religious and scientific thinking of his own time, he would set the stage for the modern science that came after him. He would open the door to the concept of "deep time," which imagined a world with a history of millions or billions of years. And at the very moment his expansive new ideas began to unravel the Bible's authoritative claim as to the age of the Earth, Steno would enter the priesthood and rise to become a bishop, ultimately becoming venerated as a saint and beatified by the Catholic Church in 1988. Combining a thrilling scientific investigation with world-altering history and the portrait of an extraordinary genius, "The Seashell on the Mountaintop" gives us new insight into the very old planet on which we live, revealing how we learned to read the story told to us by the Earth itself, written in rock and stone.