In Anglo-American law, the principal method of offering evidence in court.
It requires the opposing sides to present pertinent information and to introduce and cross-examine witnesses before a jury and/or a judge. Each side must conduct its own investigation. In criminal proceedings, the prosecution represents the government and has at its disposal the police department with its investigators and laboratories; the defense must arrange and pay for its own investigation. (Legal aid is available for the poor.) In civil (noncriminal) proceedings the adversary system works similarly, except that both sides engage private attorneys to prepare their cases. Skillful questioning often produces testimony that can be interpreted in various ways; in cross-examination, lawyers seek to alter the jury's initial perception of the testimony.