It appears that the scientific process is at the periphery of the judicial fact-finding inquiry, not integrated as it should be in every step of the investigative and prosecution process. The dearth of factual information on the decisions by which justice is weighed is particularly troublesome in relating the potential use of science and technology to the needs of police investigation and strategy. In evaluating the use of physical evidence, the author considers the nature of proof by physical means in criminal matters, and the crime laboratory as a subsystem in the criminal justice system. Bibliography, appendix, figures, tables, graphs