Hsi Duan Yu ("The Washing Away Of Wrongs"), perhaps the first book on forensics, is published. It offers some advice that is still useful today, including tips on identifying cases of strangulation from damaged neck cartilage.
18th Century
Pioneering French doctor Antoine Louis works on identifying cause of death, as well as how to distinguish between murder and suicide.
Spaniard Mathieu Orfila, a chemistry teacher in Paris, publishes "Traite de Poisons or Toxicologie Generale." The book is the first scientific study of how to detect poisons, and it earns Orfila the title of "father of forensic toxicology."
A French woman, Madame Lafarge, is accused of poisoning her husband with arsenic, and is put on trial. Chemical tests after the death were inconclusive, but during the trial, Orfila has the body exhumed, and finds traces of arsenic in the man's organs. Madame Lafarge is sentenced to the penitentiary. The case is likely the first time forensics is used in a court case.
Police in Belgium begin keeping files of daguerrotypes to help catch criminals. Over the next decades, the use of photography as a forensic aid booms. By the 1850s, police in France and the U.S. are also using "mug shots."
As a way of identifying criminals, a Belgian prison warden begins taking measurements of prisoners' heads, ears, feet, and height.
Frenchman Alphonse Bertillon begins working on an elaborate system of measurements, which include length of right ear and breadth of head. His system is used widely to identify criminals.
Sir Arthur Conan Doyle publishes the first Sherlock Holmes story, "Study In Scarlet." Holmes is the first scientific detective.
Francis Galton publishes "Fingerprints," which provides the first statistical evidence for the uniqueness of human fingerprints. Galton describes a method of analyzing fingerprints that in its basics still applies today.
Hans Gross publishes "Handbuch fur Untersuchungrichter" ("Manual for Examining Magistrates"), a handbook of forensic investigation. Although Gross likely never read the Holmes stories, his real-life work seems Holmesian in its sophistication.
While researching blood cells, a University of Vienna professor, Dr. Karl Landsteiner, discovers that the cells fall into different groups. These groups are eventually labeled as types, A, B, AB, and O.
Early 20th Cent.
Frenchman Edmund Locard sets up a forensic lab in Lyons. A disciple of both Gross and Holmes, Locard is fascinated by what he calls "the problem of dust," - how to use trace evidence to solve crimes. He proposes a concept known as "Locard's Exchange Principle," which states that whenever a criminal comes into contact with a victim, an object, or a crime scene, he or she will leave behind evidence, and will also take away evidence.
Albert Osborn publishes "Questioned Documents," a classic in handwriting analysis. Osborn goes on to become the greatest handwriting expert of the early 20th Century.
Leon Lattes, a professor at the Institute of Forensic Medicine in Turin, develops a method for pinpointing blood types from dried blood. With this technique, Lattes goes on to exonerate an accused murderer by testing bloodstains on his coat.
Using microscopes, U.S. Army Colonel Calvin Goddard perfects the technique for identifying markings left on bullets by the gun from which they were shot.
Biochemist Paul Leland Kirk begins to use his field as a way to solve forensic questions. Kirk, who also worked on the Manhattan Project, is a leader in this field. Over the next decades, biochemistry plays a key role in crimesolving.
Roland Menzel pioneers the use of lasers to locate latent fingerprints.
English researcher Alec Jeffreys discovers that each person has unique DNA. DNA, in other words, can be used like fingerprinting. Over the next 16 years, the use of DNA tests revolutionizes forensic medicine.

Source: Crime Science: Methods of Forensic Detection (Joe Nickell and John F. Fischer)