A summary of the basics of computer technology covers the various types of data input methods, program logic, the role of and types of terminals, output forms, and storage methods. The major ways computers are used for crime are covered briefly, as are the features of computers that make criminal misuse possible and detection difficult. In addition, basic computer terminology is defined. The article then turns to computer printouts as evidence and advises that they be treated and preserved as such. Several types of printers are described, since their methods of operation and configurations affect the appearance of the printouts. These include the impact printers -- character and line printers, chain or train printers, drum printers, and matrix printers -- and nonimpact printers -- ink jet printers and laser printers. Traditionally, computer crime cases have been tried under the areas of forgery or larceny. A listing of legal citations refers investigators to cases in which the admissibility of computer printouts as evidence was an issue. The cases addressed the foundational requirements needed to defeat a hearsay objection by showing that printouts fit into the business records exception. Seventeen references are cited.