Abdullah Öcalan actively led the Kurdish liberation struggle as the head of the PKK from its foundation in 1978 until his abduction on February 15, 1999. He is still regarded as a leading strategist and the most important political representative of the Kurdish freedom movement. Under isolation conditions at Imrali Island Prison, Öcalan authored more than ten books that revolutionized Kurdish politics. Several times he initiated unilateral cease-fires of the guerrilla and presented constructive proposals for a political solution to the Kurdish issue. For several years, Turkish state authorities led a "dialogue" with Öcalan. Ever since the government broke off the talks in April 2015, he has been held in total isolation at Imrali Island Prison, with no contact whatsoever with the outside world.