The exponential increase in cybercrimes in the past decade has raised new issues and challenges for law and law enforcement. Based on case studies drawn from her work as a lawyer, Susan W. Brenner identifies a diverse range of cybercrimes, including crimes that target computers (viruses, worms, Trojan horse programs, malware and DDoS attacks) and crimes in which the computer itself is used as a tool (cyberstalking, cyberextortion, cybertheft, and embezzlement). Illuminating legal issues unique to investigations in a digital environment, Brenner examines both national law enforcement agencies and transnational crime, and shows how cyberspace erodes the functional and empirical differences that have long distinguished crime from terrorism and both from warfare.