Knowles, William Standish (1917-) won the 2001 Nobel Prize in chemistry along with Ryoji Noyori of Japan “for their work on chirally catalyzed hydrogenation reactions.” They shared the award with American K. Barry Sharpless “for his work on chirally catalyzed oxidation reactions.”

Knowles was born in 1917 in Taunton, Massachusetts. He earned a bachelor's degree in chemistry at Harvard University, Cambridge, Massachusetts, in 1939 and a Ph.D. degree in organic chemistry at Columbia University in New York City in 1942. He then accepted a position at Monsanto Company in Dayton, Ohio. Two years later, he moved to the company's headquarters in St. Louis, Missouri, remaining there until 1986. In the late 1960's, Knowles headed a team seeking to develop a catalyst that could be used to synthesize (make artificially) individual enantiomers of chiral compounds. A catalyst is a substance that increases the speed of a chemical reaction without being consumed by the reaction. An enantiomer is one of a pair of crystals, molecules, or compounds that are related to each other in the way that an object is related to its mirror image. Molecules that display a type of symmetry called reflectional symmetry are known as chiral forms.

Many molecules are chiral. Most drugs consist of chiral molecules, and the correct chiral form must be used in creating the drug. The wrong form of a chiral drug molecule could bind to molecules in a cell, and a harmful result may occur, as the drug thalidomide which eased nausea in pregnant women but whose mirror image caused limb deformation in babies in the 1960's.

Knowles helped develop molecules that can catalyze important reactions so that only a desirable pure form without its mirror image is produced. He made chiral catalysts for a type of reaction called hydrogenation, a chemical process that added hydrogen atoms to a molecule.

Knowles's discovery had great significance in chemistry, materials science, biology, and medicine. In particular, his research led to an industrial process for the production of L-dopa, a drug that is used in the treatment of Parkinson disease.