Answer by taking a quote from the following article:

George Bernard Shaw (26 July 1856 - 2 November 1950), known at his insistence simply as Bernard Shaw, was an Irish playwright, critic, polemicist, and political activist. His influence on Western theatre, culture and politics extended from the 1880s to his death and beyond. He wrote more than sixty plays, including major works such as Man and Superman (1902), Pygmalion (1912) and Saint Joan (1923). With a range incorporating both contemporary satire and historical allegory, Shaw became the leading dramatist of his generation, and in 1925 was awarded the Nobel Prize in Literature.

On 5 September 1882 Shaw attended a meeting at the Memorial Hall, Farringdon, addressed by the political economist Henry George. Shaw then read George's book Progress and Poverty, which awakened his interest in economics. He began attending meetings of the Social Democratic Federation (SDF), where he discovered the writings of Karl Marx, and thereafter spent much of 1883 reading Das Kapital. He was not impressed by the SDF's founder, H. M. Hyndman, whom he found autocratic, ill-tempered and lacking leadership qualities. Shaw doubted the ability of the SDF to harness the working classes into an effective radical movement and did not join it--he preferred, he said, to work with his intellectual equals.  After reading a tract, Why Are The Many Poor?, issued by the recently formed Fabian Society, Shaw went to the society's next advertised meeting, on 16 May 1884. He became a member in September, and before the year's end had provided the society with its first manifesto, published as Fabian Tract No. 2. He joined the society's executive committee in January 1885, and later that year recruited Webb and also Annie Besant, a fine orator.  From 1885 to 1889 Shaw attended the fortnightly meetings of the British Economic Association; it was, Holroyd observes, "the closest Shaw had ever come to university education." This experience changed his political ideas; he moved away from Marxism and became an apostle of gradualism. When in 1886-87 the Fabians debated whether to embrace anarchism, as advocated by Charlotte Wilson, Besant and others, Shaw joined the majority in rejecting this approach. After a rally in Trafalgar Square addressed by Besant was violently broken up by the authorities on 13 November 1887 ("Bloody Sunday"), Shaw became convinced of the folly of attempting to challenge police power. Thereafter he largely accepted the principle of "permeation" as advocated by Webb: the notion whereby socialism could best be achieved by infiltration of people and ideas into existing political parties.  Throughout the 1880s the Fabian Society remained small, its message of moderation frequently unheard among more strident voices. Its profile was raised in 1889 with the publication of Fabian Essays in Socialism, edited by Shaw who also provided two of the essays. The second of these, "Transition", details the case for gradualism and permeation, asserting that "the necessity for cautious and gradual change must be obvious to everyone". In 1890 Shaw produced Tract No. 13, What Socialism Is, a revision of an earlier tract in which Charlotte Wilson had defined socialism in anarchistic terms. In Shaw's new version, readers were assured that "socialism can be brought about in a perfectly constitutional manner by democratic institutions".

What did he do as a member of the committee?
provided the society with its first manifesto,