Abdullah Öcalan actively led the Kurdish liberation struggle as the head of the PKK from its foundation in 1978 until his abduction on 15th February 1999. He is a leading strategist and the most important political representative of the Kurdish freedom movement. Under isolation conditions at Imrali Island Prison, he authored a number of books which revolutionised Kurdish politics, including The Political Thought of Abdullah Öcalan, and Prison Writings, Volumes I and II.