Th e idea that “the only constant is change” has been around at least since the time of Heracleitus in 500 B.C. Since we fi rst wrote this book in 1997 and subsequent editions in 2004 and 2010, the world has certainly changed. It has become increasingly globalized and we appear more interconnected with others. Th e Internet, social media, and cybercrime have altered the traditional criminal justice landscape. Th ese changes also include the nature of crime, environmental and fi nancial harms from multinational corporate crimes, global political terrorism and violence at home, work or school—all of which have become more signifi cant than the threat from strangers on the street. Th e threat of terrorism aff ects everyone, everywhere. New vulnerabilities have appeared. Th e means we use to communicate and converse have changed and opened up opportunities for new types of white-collar fraud, sexual predatory practices, and cybercrime. Th e business community has been wracked by one scandal after another, eroding confi dence in our economic and political systems, and even by challenges to the capitalist economy. Th e nature of war has also changed. Rather than nation-to-nation, wars have become endless and ongoing confl icts between ethnic and sectarian groups, though in 2014 we are seeing strains toward old European war tensions with Russia’s annexation of Ukraine’s Crimea and threats by NATO that it will defend Latvia, Estonia, and Lithuania should they be threatened by Russian expansionism. Th ese changes, coupled with many suggestions from the readers and users of the fi rst, second, and third editions, led us to revise and update Essential Criminology. As with the third edition, we revised this book in the spirit of social philosopher Eric Hoff er (1902–1983), who said that “in times of profound change, the learners inherit the earth, while the learned fi nd themselves beautifully equipped to deal with a world that no longer exists.” On the surface, this is still a book about crime and criminality. It is about how we study crime, how we explain crime, how we determine who is—and who is not—criminal, and how to reduce the harm caused by crime. It is also a book about diff erence. Crime is something we know all about—or do we? You may see crime diff erently from the way it is seen by your parents and even by your peers. You may see your own behavior as relatively acceptable, apart from a few minor rule violations here and there. But real crime? Th at’s what others do—criminals, right? You may change how you view crime and criminals after reading this text.