The forensic document examination of evidence, whether it is soil, blood, glass, hair, fibers, and so on, often requires comparison with a known standard or control. Although most investigators have little difficulty in recognizing and collecting relevant crime scene evidence, few seem aware of the like necessity and importance of providing the crime lab with a thorough sampling of control materials. Such materials may be obtained from the victim, a suspect, or other sources. For instance, investigation of a hit-and-run incident might require the removal of control paint from a suspect vehicle. This will permit its comparison to paint recovered at the scene. Similarly, hair found at the crime scene will be of optimum value only when compared to control hairs removed from the suspect and victim. Likewise, bloodstained evidence must be accompanied by whole blood controls obtained from all relevant crime scene participants. The quality and quantity of control specimens often determine the evidential value of crime scene evidence, and these control specimens must be treated with equal care. The thorough collection and proper packaging of control specimens are the mark of a skilled investigator.