Why do we need this book? There are tons of books on criminal investigation on the market, but the same is not true regarding the investigation of computer- related crimes. When we wrote this book, the latest one covering computer crime was 7 to 10 years old. Technology changes very fast. The software and hardware used by investigators may work one day and may not work the next, as the next generation of software and hardware comes into use. What is important are the principles of investigating computers and other electronic evidence. Computer-related crime is defined as “any criminal activity that involves use of computer technology, directly or indirectly, as the instrumentality or object of the commission of a criminal act.” Most of us think of “hacking” when we think of a computer crime, where some genius child plays war games with the Pentagon’s computer system. The truth is that computers are used by ordinary people of average intelligence to commit virtually every traditional crime in the penal code.