Question: Who wrote the play in which Evelyn Varden had the role of Mrs Gibbs ? 

Context articles: Night Must Fall
Margaretta Graddon
Evelyn Varden
Tracy-Ann Oberman
Hodgson v Marks
Athena (film)
The Luck of the Navy (film)
Kathleen Harrison
Alex Gibbs
Our Town

Night Must Fall is a play, a psychological thriller, by Emlyn Williams, first performed in 1935.
 There have been three film adaptations, "Night Must Fall" (1937); a 1954 adaptation on the television anthology series "Ponds Theater" starring Terry Kilburn, Una O'Connor, and Evelyn Varden; and "Night Must Fall" (1964).
Margarita Graddon or Mrs Gibbs (born 1804) was a British popular singer.
Evelyn Varden (June 12, 1893, Adair, Oklahoma – July 11, 1958, Manhattan, New York City) was an American character actress.
 She began her career as a teenager in the first decade of the 20th century and was on Broadway by age sixteen in 1910.
 It was not until the 1930s and into her forties that her stage career took off in the theater, notably playing Mrs. Gibbs, the small town matron who dreams of Paris, in the original production of "Our Town".
 The role was played by Fay Bainter in the 1940 motion picture.
Tracy-Ann Oberman (born Tracy Anne Oberman, 25 August 1966, Brent, Greater London) is an English television, theatre and radio actress.
 Best known for her role as Chrissie Watts in BBC1 soap opera "EastEnders" from 2004–05.
 Also a writer, Oberman has contributed to a number of radio sketch shows and in 2008 co-authored with Diane Samuels the play "Three Sisters on Hope Street".
 In 2010 she wrote and starred alongside Catherine Tate in her BBC Radio 4 play "Bette and Joan and Baby Jane" and in 2012 wrote the BBC Radio 4 play "Rock and Doris and Elizabeth".
 In 2015 she wrote and starred in the third part of her Hollywood Trilogy for BBC Radio 4, "Mrs Robinson, I Presume", alongside John Simm and Kevin Bishop.
 Oberman was a regular columnist for "The Guardian" newspaper during 2007.
Mrs Hodgson bought 31 Gibbs Green, Edgware, Middlesex in 1939.
 After being widowed in April 1959 she took Mr Evans as a lodger, and in June 1960 transferred him her freehold for free.
 He told her she should give him the deeds so her nephew, in the foreign service, would not return and turn her out.
 He also took money to invest on her behalf.
 He registered himself, and sold it to Mr Marks, who gave a charge to Cheltenham & Gloucester Building Society.
 Mrs Hodgson, still living there, found out and claimed a declaration that Mr Marks should transfer his freehold to her, free from the building society charge.
 Mr Evans had held on trust for her, and that bound Mr Marks and the building society.
Athena (1954) is a romantic musical comedy, starring Jane Powell, Edmund Purdom, Debbie Reynolds, Vic Damone, Louis Calhern, Steve Reeves, and Evelyn Varden, and released by Metro-Goldwyn-Mayer.
The Luck of the Navy is a 1927 British silent comedy thriller film directed by Fred Paul and starring Evelyn Laye, Henry Victor and Hayford Hobbs.
 It was an adaptation of the 1919 play "The Luck of the Navy" by Mrs Clifford Mills.
Kathleen Harrison (23 February 1892 – 7 December 1995) was a prolific English character actress best remembered for her role as Mrs Huggett (opposite Jack Warner and Petula Clark) in a trio of British post-war comedies about a working-class family's misadventures.
 To modern viewers she may be best remembered as the charwoman Mrs Dilber opposite Alastair Sim in the 1951 film "Scrooge" (US: "A Christmas Carol", 1951) and as a Cockney charwoman who inherits a fortune in the television series "Mrs Thursday" (1966–67).
Alex Gibbs (born February 22, 1941) is a former NFL offensive line coach and former assistant NFL head coach.
 He formerly served as an offensive line consultant for the American football team the Denver Broncos.
 Gibbs is a well known proponent of the Zone Blocking scheme and popularized its use while he was Offensive line coach of the Denver Broncos.
 Denver became famous at that time for its use of smaller and more agile offensive linemen and the success of its running backs, most notably Terrell Davis.
 Gibbs was to enter his first season on Pete Carroll's Seattle Seahawks staff as the Assistant Head Coach and Offensive Line coach in 2010, but announced his unexpected retirement a week before the start of the NFL's 2010 regular season.
 In May 2013 he returned to the Denver Broncos in a consultant role for one year.
Our Town is a 1938 metatheatrical three-act play by American playwright Thornton Wilder.
 It tells the story of the fictional American small town of Grover's Corners between 1901 and 1913 through the everyday lives of its citizens.