Charles Herbert Best was a Canadian physiologist and one of the co-discoverers of insulin. Born in Maine in 1899 to Canadian parents, Best moved to Toronto in 1915, where he completed a degree in physiology and biochemistry. In 1921, as a medical student at the University of Toronto, he worked as an assistant to Dr. Frederick Banting. Together they discovered the pancreatic hormone insulin, which became a treatment for diabetes. In 1923, Banting and J.J.R Macleod were awarded the Nobel Prize in Medicine for the discovery of insulin, while Best was not named in the award, Banting chose to give half of the prize money to Best. Best became a professor of physiology at the University of Toronto in 1927. During his time in the department, he co-authored the textbook The Physiological Basis of Medical Practice (1937) with Norman B. Taylor. After Banting’s death in 1941, Best also became the head of the Banting and Best Department of Medical Research at the University of Toronto. During WWII, Best developed a method of separating and drying blood plasma serum, which could be sent to the front, reconstituted and transfused into wounded soldiers. Best served as an adviser to the Medical Research Committee of the United Nations World Health Organization, and was made a Companion of the Order of Canada in 1967. He retired in 1965 and died in 1978.