There are four categories of computer crime: (1) a physical attack on computer hardware, (2) erasure of valuable computerized files or other attempts to sabotage computer software, (3) use of the computer as a tool in illicit schemes, and (4) use of a computer for fraud or intimidation. The greatest threat is in computers being used for illicit ends, since it is potentially the most lucrative. The vast majority of computer criminals are amateurs who commit their crimes using their employer's computer. Such individuals are brought to justice largely by mistake or accident. Due to the technology involved, it may be difficult to determine how much a computer criminal stole. Since these crimes often occur over long periods, chances of recovering the proceeds are diminished. Several cases demonstrate the complexity of computer crimes and the difficulties in detection. Computer crime may be conducted over great distances, making it difficult to detect, let alone prosecute. Several States have enacted legislation to counter computer crime, and Congress is considering the Federal Computer Systems Protection Act. The answer does not lie in legislation but with the adoption of effective safeguards by computer manufacturers and computer owners. Effective measures include recording and monitoring employee activities, providing checks and balances for employees using computers, and providing dual controls over employees' activities. Further, companies should carefully screen individuals hired for computer operations, and computer equipment should be available only to those authorized to use it. Increases in customer complaints may indicate computer abuse or manipulation. The article includes 70 footnotes and several examples of computer crimes.