who organizes it?
Michael Eavis, through his company Glastonbury Festivals Ltd
Glastonbury Festival
Since 1981, the festival has been organised by local farmer and site owner Michael Eavis (through his company Glastonbury Festivals Ltd). 
how many times have radiohead played at glastonbury Around 6 times - In 1997, May 2003, June 2010, 2016, 2017, and 2018 what is this festival about? A five-day festival of contemporary performing arts that takes place in Pilton, Somerset, in England when was it started? between 1914 and 1926
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Glastonbury Festival [SEP] Organisation
Since 1981, the festival has been organised by local farmer and site owner Michael Eavis (through his company Glastonbury Festivals Ltd). Eavis ran the festival with his wife Jean until her death in 1999, and now co-organises the event with his daughter Emily Eavis. In 2002, Festival Republic (a company consisting of both Live Nation and MCD) took on the job of managing the logistics and security of the festival through a 40% stake in the festival management company. This relationship ended in 2012 and Glastonbury festival is now independent. Glastonbury Festivals Ltd donates most of their profits to charities, including donations to local charity and community groups and paying for the purchase and restoration of the Tithe Barn in Pilton.