1991 deaths

David Harker (October 19, 1906 – February 27, 1991) was an American medical researcher who according to The New York Times was "a pioneer in the use of X-rays to decipher the structure of critical substances in the life process of cells".He is also well known for Harker–Kasper inequalities (statistical relationships between the phases of structure factors), which he devised in collaboration with John S. Kasper.
Harker made seminal discoveries in the field of chemical crystallography.His lab solved the structure of the pancreatic enzyme ribonuclease A, the third protein structure ever solved by protein crystallography.
Harker was a member of the National Academy of Sciences,
director of the protein structure program at the Polytechnic Institute of Brooklyn, director of the Center for Crystallographic Research at Roswell Park Comprehensive Cancer Center, and the head of the crystallography division of General Electric. After retirement from Roswell Park in 1976, he joined the Hauptman-Woodward Medical Research Institute (HWI), then known as the Medical Foundation of Buffalo. He remained there until his death in 1991. His research interests while at HWI turned towards mathematical aspects of crystallography, including color space groups and infinite polyhedra.Harker was awarded the Gregori Aminoff Prize from the Swedish Academy in 1984.

Tom (Tammy) Anderson MBE (1910–1991) was a Scottish fiddler, teacher, composer and collector of traditional tunes. He has been described as "...the most prominent personality in the entire history of Shetland fiddling."

Brothers James Lloyd "Jim" Mitchell (November 30, 1943 in Stockton, California – July 12, 2007 in Petaluma, California) and Artie Jay Mitchell (December 17, 1945 in Lodi, California – February 27, 1991 in Marin County, California) were American entrepreneurs. They operated in the pornography and striptease club business in San Francisco and other parts of California from 1969 until 1991 when Jim was convicted of killing Artie.They opened the O'Farrell Theatre in 1969 as an adult cinema and at one time operated 11 such businesses. They produced and directed many adult films, including Behind the Green Door in 1972. They were also successful as defendants in many obscenity cases. Their notoriety significantly increased with Jim's fratricide and they became the subject of three books, X-Rated, Bottom Feeders, and 9½ Years Behind the Mitchell Brothers' Green Door and the movie Rated X.

Jean Mantelet (1900–19 January 1991) was a French inventor and industrialist who founded the kitchen appliance company Moulinex.

Detlev Karsten Rohwedder (16 October 1932 – 1 April 1991) was a German manager and politician, as member of the Social Democratic Party. He was named president of the Treuhandanstalt, the agency responsible for the reprivatization/privatization of all state-owned property in the former German Democratic Republic (GDR), in September 1990, and served until his assassination by a Far Left terrorist organization, the Red Army Faction, in April 1991. He had also served as CEO of the steel manufacturer Hoesch AG since 1980.

Giacomo Manzoni (22 December 1908 – 17 January 1991), known professionally as Giacomo Manzù, was an Italian sculptor.

Hervé Guibert (14 December 1955 – 27 December 1991) was a French writer and photographer. The author of numerous novels and autobiographical studies, he played a considerable role in changing French public attitudes to HIV/AIDS. He was a close friend of Michel Foucault.

Louis Graydon Sullivan (June 16, 1951 – March 2, 1991) was an American author and activist known for his work on behalf of trans men. He was perhaps the first transgender man to publicly identify as gay, and is largely responsible for the modern understanding of sexual orientation and gender identity as distinct, unrelated concepts.Sullivan was a pioneer of the grassroots female-to-male (FTM) movement and was instrumental in helping individuals obtain peer-support, counselling, endocrinological services and reconstructive surgery outside of gender dysphoria clinics. He founded FTM International, one of the first organizations specifically for FTM individuals, and his activism and community work was a significant contributor to the rapid growth of the FTM community during the late 1980s.

Gerhard Höllerich (25 January 1943 – 9 October 1991), known professionally as Roy Black, was a German schlager singer and actor, who appeared in several musical comedies and starred in the 1989 TV series, Ein Schloß am Wörthersee.

Simone "Simca" Beck (7 July 1904 – 20 December 1991) was a French cookbook writer and cooking teacher who, along with colleagues Julia Child and Louisette Bertholle, played a significant role in the introduction of French cooking technique and recipes into American kitchens.