Forensic science, or criminalistics, is based on the theory of transfer: when two objects meet, some evidence of that meeting generally can be established and verified at a later time. The National Institute of Justice (NIJ)’s Science and Technology Division has been instrumental in a number of areas with grants that have advanced the science of DNA profiling and supported research into less-than-lethal devices. Forensic science has been an area of particular interest, with grants funding research as varied as photographing wound patterns invisible to the human eye, creating new fingerprint reagents, developing comprehensive software programs on firearms or trace evidence, and photographing bite marks. The NIJ has also sponsored research on the use of high-speed photography to document gunshot residue as it is being formed; increasing the accuracy and reducing test time for the presence of carbon monoxide; determining when documents were written; and processing sexual assault evidence. The NIJ is also involved in developing training, testing, and certification procedures for forensic scientists similar to those in other disciplines.